IP Library Granted Patent US 7,221,722
Granted Patent B2
US 7,221,722 · App. 10/375,438 · Granted May 22, 2007

Method and apparatus for reducing interference within a communication system

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Quick Facts
Patent No.
US 7,221,722
App. No.
10/375,438
Granted
May 22, 2007
Kind
B2
Abstract

A method for reducing interference within a communication system is provided herein. The method comprising the steps of receiving a signal y(n), where y(n) comprises a desired signal, s(n), and a co-channel interfering signal, i(n), wherein s(n) and i(n) are not time-synchronized, converting y(n) into a frequency-domain signal Y(k), calculating a weight vector W(k), wherein W(k) is based on s(n) and i(n), and additionally based on a time offset T existing between s(n) and i(n), and applying W(k) to Y(k) in order to equalize the desired signal, s(n), and reduce co-channel interference i(n).

Claims (32)

1. An apparatus for reducing interference within a communication system, the apparatus comprising:

an antenna receiving a signal y(n), where y(n) comprises a desired signal, s(n), and a co-channel interfering signal, i(n), wherein s(n) and i(n) are not time-synchronized;

a transformer for transforming y(n) into a frequency-domain signal Y(k);

a weight calculator outputting a weight vector W(k), wherein W(k) is based on s(n) and i(n), and additionally based on a time offset T existing between s(n) and i(n); and

a signal combiner applying W(k) to Y(k) in order to reduce co-channel interference i(n), wherein W(k) is additionally based on a spatial correlation matrix of the desired signal on a subcarrier k, R d (k), wherein W(k) is additionally based on a spatial correlation matrix of the interferer on subcarrier k, R I (k), wherein W(k) is additionally based on a spatial correlation matrix of noise, R E (k), and wherein W(k)=(R d (k)+R I (k)+R E (k)) −1 p(k), wherein p(k) is an M×1 crosscorrelation vector.

2. The apparatus of claim 1 wherein the weight calculator further comprises:

logic circuitry utilized to calculate correlation matrices R d (k) and R I (k);

logic circuitry utilized to calculate the crosscorrelation matrix p(k);

logic circuitry utilized to calculate noise correlation matrix R E (k); and

logic circuitry used to calculate W(k).

3. An apparatus comprising:

logic circuitry utilized to calculate a spatial correlation matrix of a desired signal on a sub carrier k, R d (k);

logic circuitry utilized to calculate a spatial correlation matrix of an interferer on the subcarrier k, R I (k);

logic circuitry utilized to calculate on a spatial correlation matrix of noise, R E (k); and

logic circuitry used to calculate a weighting vector W(k) to be applied to a received signal, the weighting vector W(k) being based on R d (k), R I (k), and R E (k), wherein W(k)=(R d (k)+R I (k)+R E (k)) −1 p(k), wherein p(k) is an M×1 crosscorrelation vector.

4. A method for reducing interference within a communication system, the method comprising the steps of:

calculating a spatial correlation matrix of the desired signal on subcarrier k, R d (k);

calculating a spatial correlation matrix of the interferer on subcarrier k, R I (k);

calculating a spatial correlation matrix of the noise, R E (k); and

calculating a weighting vector W(k) to be applied to a received signal to reduce interference, the weighting vector W(k) being based on R d (k), R I (k), and R E (k)), wherein W(k)=(R d (k)+R I (k)+R E (k)) −1 p(k), wherein p(k) is an M×1 crosscorrelation vector.

5. A method for reducing interference within a communication system, the method comprising the steps of:

receiving a signal y(n), where y(n) comprises a desired signal, s(n), and a co-channel interfering signal, i(n), wherein s(n) and i(n) are not time-synchronized;

converting y(n) into a frequency-domain signal Y(k);

calculating a weight vector W(k), wherein W(k) is based on s(n) and i(n), and additionally based on a time offset T existing between s(n) and i(n); and

applying W(k) to Y(k) in order to reduce co-channel interference i(n), wherein the step of calculating W(k) comprises the step of calculating W(k) based on a spatial correlation matrix of the desired signal on a subcarrier k, R d (k), wherein the step of calculating the weight vector W(k) comprises the step of calculating W(k)=(R d (k)+R E (k)) −1 p(k), wherein p(k) is an M×1 crosscorrelation vector.

6. The method of claim 5 the step of calculating W(k) comprises the step of calculating W(k) based on a spatial correlation matrix of noise, R E (k).

7. A method for reducing interference within a communication system, the method comprising the steps of:

receiving a signal y(n), where y(n) comprises a desired signal, s(n), and a co-channel interfering signal, i(n), wherein s(n) and i(n) are not time-synchronized;

converting y(n) into a frequency-domain signal Y(k);

calculating a weight vector W(k), wherein W(k) is based on s(n) and i(n), and additionally based on a time offset T existing between s(n) and i(n); and

applying W(k) to Y(k) in order to reduce co-channel interference i(n), wherein the step of calculating W(k) comprises the step of calculating W(k) based on a spatial correlation matrix of the desired signal on a subcarrier k, wherein the step of calculating W(k) comprises the step of calculating W(k)=(R d (k)+R I (k)+R E (k)) −1 p(k), wherein p(k) is an M×1 crosscorrelation vector.

8. The method of claim 7 wherein the step of calculating W(k) comprises the step of calculating W(k) based on a spatial correlation matrix of the interferer on subcarrier k, R I (k).

Assignments (4)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Nov 24, 2014
From: MOTOROLA MOBILITY LLC
To: GOOGLE TECHNOLOGY HOLDINGS LLC
Reel/Frame 034420/0001 →
CHANGE OF NAME Recorded Oct 2, 2012
From: MOTOROLA MOBILITY, INC.
To: MOTOROLA MOBILITY LLC
Reel/Frame 029216/0282 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 13, 2010
From: MOTOROLA, INC
To: MOTOROLA MOBILITY, INC
Reel/Frame 025673/0558 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 27, 2003
From: THOMAS, TIMOTHY A.; VOOK, FREDERICK W.
To: MOTOROLA, INC.
Reel/Frame 013833/0967 →