Method and apparatus for cancelling spread-spectrum noise

• US 5,105,435 A
• Filed: 12/21/1990
• Issued: 04/14/1992
• Est. Priority Date: 12/21/1990
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Stilwell, James H.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US07/632,452
• Time in Patent Office: 480 Days
• Field of Search: 375/1, 375/99, 375/102, 375/103, 375/34, 380/34, 455/278, 455/284, 455/296, 455/303, 455/305, 370/18
• US Class Current: 375/144
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04L 27/2071 in which the data are represented by the carrier phase, e.g. systems with differential coding
• CPC Class Codes: H04L 27/2273 associated with quadrature demodulation, e.g. Costas loop

Abstract

A spread-spectrum noise canceller is provided for cancelling user code noise from a spread-spectrum communication channel. The spread-spectrum noise canceller including a receiver for receiving a spread-spectrum signal including a first and at least a second signal as well as a noise canceller operatively coupled to the receiver for reducing spread-spectrum noise in the first received signal by substantially processing the at least second received signal out of the received spread-spectrum signal.

In addition a method is provided which cancels user code noise from a spread-spectrum communication channel. The method includes for receiving a spread-spectrum signal including a first and at least a second signal and subsequently reducing spread-spectrum noise in the first received signal by substantially processing the at least second received signal out of the received spread-spectrum signal.

Claims

1. A spread-spectrum noise canceller, comprising:

(a) receiving means for receiving a spread-spectrum signal including a first and at least a second signal; and

(b) noise cancelling means operatively coupled to the receiving means for reducing spread-spectrum noise in the first received signal by substantially processing the at least second received signal out of the received spread-spectrum signal through the use of a spreading code associated with the at least second received signal.

2. A spread-spectrum noise canceller, comprising:

(a) receiving means for receiving a spread-spectrum signal, generating a first estimated signal from a first input signal by utilizing a first spreading code, and generating a second estimated signal from a second input signal by utilizing a second spreading code; and

(b) noise cancelling means operatively coupled to the receiving means for reducing spread-spectrum noise in the received spread-spectrum signal by;

(i) generating the first input signal as a function of the first estimated signal, the second estimated signal and the spread-spectrum signal; and

(ii) generating the second input signal as a function of the first estimated signal, the second estimated signal and the spread-spectrum signal.

3. A spread-spectrum noise canceller, comprising:

(a) receiving means for receiving a spread-spectrum signal;

(b) first receiver means for despreading a first input signal with a first spreading code, generating a first estimated signal of the despread first input signal, and spreading the first estimated signal with the first spreading code;

(c) second receiver means for despreading a second input signal with a second spreading code, generating a second estimated signal of the despread second input signal, and spreading the second estimated signal with the second spreading code; and

(d) noise cancelling means operatively coupled to the receiving means, the first receiver means and the second receiver means for reducing spread-spectrum noise in the received spread-spectrum signal by;

(i) generating a composite estimate signal by summing the first and second estimated spread-spectrum signals;

(ii) generating a first interference signal by subtracting the first estimated spread-spectrum signal from the composite estimate signal and subsequently generating the first input signal by subtracting the first interference signal from the spread-spectrum signal received by the receiving means; and

(iii) generating a second interference signal by subtracting the second estimated spread-spectrum signal from the composite estimate signal and subsequently generating the second input signal by subtracting the second interference signal from the spread-spectrum signal received by the receiving means.

4. The spread-spectrum noise canceller of claim 3 wherein the receiving means comprises conversion means for converting the spread-spectrum signal from a first frequency range to a second frequency range, the second frequency range being such that the received signal can be manipulated digitally.

5. A method for cancelling spread-spectrum noise, comprising:

(a) receiving a spread-spectrum signal;

(b) generating a first estimated signal from a first input signal by utilizing a first spreading code;

(c) generating a second estimated signal from a second input signal by utilizing a second spreading code;

(d) reducing spread-spectrum noise in the received spread-spectrum signal by;

(i) generating the first input signal as a function of the first estimated signal, the second estimated signal and the spread-spectrum signal; and

(ii) generating the second input signal as a function of the first estimated signal, the second estimated signal and the spread-spectrum signal.

6. A method for cancelling spread-spectrum noise, comprising:

(a) receiving a spread-spectrum signal;

(b) generating a first estimated signal by;

(i) despreading a first input signal with a first spreading code;

(ii) estimating a first estimated signal of the despread first input signal; and

(iii) spreading the first estimated signal with the first spreading code;

(c) generating a second estimated signal by;

(i) despreading a second input signal with a second spreading code;

(ii) estimating a second estimated signal of the despread second input signal; and

(iii) spreading the second estimated signal with the second spreading code; and

(d) reducing spread-spectrum noise in the received spread-spectrum signal by;

(i) generating a composite estimate signal by summing the first and second estimated spread-spectrum signals;

(ii) generating a first interference signal by subtracting the first estimated spread-spectrum signal from the composite estimate signal and subsequently generating the first input signal by subtracting the first interference signal from the spread-spectrum signal; and

(iii) generating a second interference signal by subtracting the second estimated spread-spectrum signal from the composite estimate signal and subsequently generating the second input signal by subtracting the second interference signal from the spread-spectrum signal.

7. A spread-spectrum noise canceller, comprising:

(a) receiving means for receiving a spread-spectrum signal including a user spreading code and a control spreading code; and

(b) noise cancelling means operatively coupled to the receiving means for reducing spread-spectrum noise in the received spread-spectrum signal by;

(ii) generating control data by processing a user signal out of the received spread-spectrum signal and subsequently spreading remaining spread-spectrum signal with the control spreading code; and

(iii) generating user data by processing a control signal out of the received spread-spectrum signal and subsequently spreading remaining spread-spectrum signal with the user spreading code.

8. A spread-spectrum noise canceller, comprising:

(a) receiving means for receiving a spread-spectrum signal including a control signal and a plurality of user signals;

(b) processing means operatively coupled to the receiving means for determining at least a first spreading code, second spreading code and a control spreading code from the received spread-spectrum signal; and

(c) noise cancelling means operatively coupled to the receiving means and the processing means for removing spread-spectrum noise from the received signal by;

(i) removing a second user signal by despreading the received spread-spectrum signal with the second spreading code, processing the second user signal out of the received spread-spectrum signal, and generating a reduced noise signal by spreading the remaining spread-spectrum signal with the second spreading code;

(ii) generating control data by despreading the reduced noise signal with the first spreading code, processing the first user signal out of the received spread-spectrum signal, and spreading the remaining spread-spectrum signal with the first spreading code and subsequently the control spreading code; and

(iii) generating first user data by despreading the reduced noise signal with the control spreading code, processing the control signal out of the received spread-spectrum signal, and spreading the remaining spread-spectrum signal with the control spreading code and subsequently the first spreading code.

9. A method of cancelling spread-spectrum noise, comprising:

(a) receiving a spread-spectrum signal including a user spreading code and a control spreading code; and

(b) removing spread-spectrum noise from the received signal by;

(i) generating control data by processing a user signal out of the received spread-spectrum signal and subsequently spreading remaining spread-spectrum signal with the control spreading code; and

(ii) generating user data by processing a control signal out of the received spread-spectrum signal and subsequently spreading remaining spread-spectrum signal with the user spreading code.

10. A method of cancelling spread-spectrum noise, comprising:

(a) receiving a spread-spectrum signal including a control signal and a plurality of user signals;

(b) determining at least a first spreading code, second spreading code and a control spreading code from the received spread-spectrum signal; and

(c) removing spread-spectrum noise from the received signal by;

(i) removing a second user signal by despreading the received spread-spectrum signal with the second spreading code, processing the second user signal out of the received spread-spectrum signal, and generating a reduced noise signal by spreading the remaining spread-spectrum signal with the second spreading code;

(ii) generating control data by despreading the reduced noise signal with the first spreading code, processing the first user signal out of the received spread-spectrum signal, and spreading the remaining spread-spectrum signal with the first spreading code and subsequently the control spreading code; and

(iii) generating first user data by despreading the reduced noise signal with the control spreading code, processing the control signal out of the received spread-spectrum signal, and spreading the remaining spread-spectrum signal with the control spreading code and subsequently the first spreading code.