Method and apparatus for interference suppression in spread spectrum signals

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.

A method of interference removal in spread spectrum signals comprising the steps of:

• 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.

A method of interference removal in spread spectrum signals, comprising the steps of:

• 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.

A method of interference removal in spread spectrum signals, comprising the steps of:

• 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.

An interference suppression circuit for suppressing interference on corrupted data encoded in a spread spectrum signal, comprising:

• 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.

A receiver for receiving and decoding corrupted data encoded in a direct sequence spread spectrum signal, comprising:

• 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.

A spread spectrum system for transmitting, receiving and decoding corrupted data encoded in a direct sequence spread spectrum signal, comprising:

• 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.

A receiver for receiving and decoding corrupted data encoded in a direct sequence spread spectrum signal, comprising:

• 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.