Method and apparatus for interference suppression in spread spectrum signals
First Claim
1. A method of interference removal from data in a spread spectrum signal that has been encoded and transmitted by modulating a repeating noise sequence with the data, comprising the steps of:
- at a receiver;
receiving the spread spectrum signal along with interference;
multiplying the spread spectrum signal along with interference by a window function providing a multiplied spread spectrum signal;
converting the multiplied spread spectrum signal into the frequency domain providing a received signal with a phase information portion and a magnitude information portion;
removing interference from the magnitude information portion by applying a prestored function of the repeating noise sequence to the magnitude information portion; and
extracting substantially interference free data from the phase information portion.
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Accused Products
Abstract
Interference removal in spread spectrum signals, comprises the steps at a spread spectrum transmitter (10) of spreading information across a predetermined spectrum by phase modulating a repeating noise sequence (18), providing a spread spectrum signal and transmitting the spread spectrum signal. The method further comprises the steps at a receiver of receiving the spread spectrum signal along with interference (41) multiplying (42) the spread spectrum signal along with interference by a window function (44) providing a multiplied spread spectrum signal. The information is recovered by despreading the multiplied (48) spread spectrum signal using a reciprocal (50) of the spectrum of the repeating noise sequence to obtain a data spectrum with interference and subsequently normalize (52) to obtain a clean data spectrum. Alternatively the information can be recovered by substituting a corrupted magnitude spectrum with a prestored PN sequence magnitude spectrum (70) as shown by receiver (60).
70 Citations
26 Claims
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1. A method of interference removal from data in a spread spectrum signal that has been encoded and transmitted by modulating a repeating noise sequence with the data, comprising the steps of:
at a receiver; receiving the spread spectrum signal along with interference; multiplying the spread spectrum signal along with interference by a window function providing a multiplied spread spectrum signal; converting the multiplied spread spectrum signal into the frequency domain providing a received signal with a phase information portion and a magnitude information portion; removing interference from the magnitude information portion by applying a prestored function of the repeating noise sequence to the magnitude information portion; and
extracting substantially interference free data from the phase information portion.
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2. A method of interference removal from data in a spread spectrum signal that has been encoded and transmitted by phase modulating a repeating noise sequence with the data, comprising the steps of:
at a receiver; receiving the spread spectrum signal along with interference; multiplying the spread spectrum signal along with interference by a window function providing a multiplied spread spectrum signal; converting the multiplied spread spectrum signal into the frequency domain providing a received signal; multiplying the received signal by a reciprocal of the spectrum of the repeating noise sequence to obtain a data spectrum with interference; and normalizing the data spectrum with interference to provide a clean data spectrum.
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3. A method of interference removal in spread spectrum signals comprising the steps of:
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at a transmitter; modulating information using phase shift keying; spreading the information across a predetermined spectrum by phase modulating a repeating noise sequence, providing a spread spectrum signal; and transmitting the spread spectrum signal; at a receiver; receiving the spread spectrum signal along with interference; multiplying the spread spectrum signal along with interference by a window function providing a multiplied spread spectrum signal; converting the multiplied spread spectrum signal into a frequency domain providing a received signal; multiplying the received signal by a reciprocal of the spectrum of the repeating noise sequence to obtain a data spectrum with interference; and limiting limiting the magnitude of the data spectrum with interference to provide a clean data spectrum. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of interference removal in spread spectrum signals, comprising the steps of:
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at a transmitter; spreading information across a predetermined spectrum by phase modulating a repeating noise sequence, providing a spread spectrum signal; transmitting the spread spectrum signal; at a receiver; receiving the spread spectrum signal along with interference; multiplying the spread spectrum signal along with interference by a window function providing a multiplied spread spectrum signal; despreading the multiplied spread spectrum signal using a reciprocal of the spectrum of the repeating noise sequence to obtain a data spectrum with interference; and complex normalizing the data spectrum with interference to obtain a clean data spectrum. - View Dependent Claims (13, 14, 15)
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16. A method of interference removal in spread spectrum signals, comprising the steps of:
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at a transmitter; spreading information across a predetermined spectrum by phase modulating a repeating noise sequence with the information, providing a spread spectrum signal; transmitting the spread spectrum signal; at a receiver; receiving the spread spectrum signal along with interference; multiplying the spread spectrum signal along with interference by a window function providing a multiplied spread spectrum signal; transforming the multiplied spread spectrum signal into a frequency domain, providing a corrupted data signal spectrum including a corrupted magnitude spectrum and a corrupted phase spectrum; substituting the corrupted magnitude spectrum with a prestored magnitude spectrum of the repeating noise sequence in the frequency domain; and combining the corrupted phase spectrum with the prestored magnitude spectrum of the repeating noise sequence providing a substantially interference free spread spectrum signal in the frequency domain. - View Dependent Claims (17, 18)
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19. An interference suppression circuit for suppressing interference on corrupted data encoded in a spread spectrum signal, comprising:
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a receiver for receiving the spread spectrum signal along with interference; a multiplier for multiplying the spread spectrum signal along with interference by a window function providing a multiplied spread spectrum signal; a frequency domain converter for converting the multiplied spread spectrum signal from a time domain into a frequency domain and providing a corrupted phase information portion and a corrupted magnitude information portion; an interference suppression module for suppressing interference on the corrupted magnitude information portion to provide a corrected magnitude information portion and to further combine the corrected magnitude information portion with the corrupted phase information portion to provide an interference suppressed information signal; and a time domain converter for converting the interference suppressed information signal from the frequency domain into the time domain. - View Dependent Claims (20, 21)
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22. A receiver for receiving and decoding corrupted data encoded in a direct sequence spread spectrum signal, comprising:
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a receiver module for receiving the spread spectrum signal along with interference; a multiplier for multiplying the spread spectrum signal along with interference by a window function providing a multiplied spread spectrum signal; a frequency domain converter for converting the multiplied spread spectrum signal from a time domain into a frequency domain and providing a corrupted phase information portion and a corrupted magnitude information portion; an interference suppression circuit for suppressing interference on the corrupted magnitude information portion to provide a suppressed magnitude information portion and to further combine the suppressed magnitude information portion with the corrupted phase information portion to provide an interference suppressed information signal; and a time domain converter for converting the interference suppressed information signal from the frequency domain into the time domain.
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23. A spread spectrum system for transmitting, receiving and decoding corrupted data encoded in a direct sequence spread spectrum signal, comprising:
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a transmitter for transmitting the spread spectrum signal; a receiver for receiving the spread spectrum signal along with interference; a multiplier for multiplying the spread spectrum signal along with interference by a window function providing a multiplied spread spectrum signal; a frequency domain converter for converting the multiplied spread spectrum signal from the time domain into the frequency domain and providing a corrupted phase information portion and a corrupted magnitude information portion; and an interference suppression circuit for suppressing interference on the corrupted magnitude information portion to provide a suppressed magnitude information portion and to further combine the suppressed magnitude information portion with the corrupted phase information portion to provide an interference suppressed information signal.
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24. A receiver for receiving and decoding corrupted data encoded in a direct sequence spread spectrum signal, comprising:
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a receiver module for receiving the spread spectrum signal along with interference; a multiplier for multiplying the spread spectrum signal along with interference by a window function providing a multiplied spread spectrum signal; a frequency domain converter for converting the multiplied spread spectrum signal from a time domain to a frequency domain providing a corrupted frequency domain spread spectrum signal; a memory device for storing a reciprocal of repeating noise spectrum; a multiplier for despreading the corrupted frequency domain spread spectrum signal to provide a despread signal; and a normalizer for limiting the magnitude of a spectrum of the despread signal to provide a normalized signal. - View Dependent Claims (25, 26)
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Specification