Interference cancellation method in radio system

• US 20030176169A1
• Filed: 12/18/2002
• Published: 09/18/2003
• Est. Priority Date: 12/27/2001
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Horneman, Kari, Pajukoski, Kari, Nuutinen, Jukka
• Granted Patent: US 7,450,671 B2
• Time in Patent Office: Days
• US Class Current: 455/77
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]

Abstract

A receiver in a radio system, comprising one or more antennas (600A to 600B) for receiving a signal including signal components descriptive of a signal to be detected and an interfering signal. The receiver comprises means for measuring (614A to 614B) the antenna-specific reception power of the received signal and means for weighting (614A to 614B) the signal received in each antenna by a antenna-specific weighting coefficient proportional to the reception power of said signal.

Claims

1. A method of receiving a signal in a radio system, comprising:

receiving a signal including signal components descriptive of a signal to be detected and an interfering signal using at least one antenna in a receiver;

measuring the antenna-specific reception power of the received signal, and

weighting the signal received in each antenna by a weighting coefficient proportional to the reception power of said signal.

2. A method as claimed in claim 1, wherein the antenna-specific weighting coefficient is the reciprocal of the reception power of the signal received in said antenna.

3. A method as claimed in claim 1, wherein the signal is received using one antenna of the receiver, and the received signal is weighted time-dependently by the weighting coefficient proportional to the reception power of the signal.

4. A method as claimed in claim 1, comprising:

comparing the reception power of the signal to be detected with the reception power of the interfering signal to generate a signal-to-noise ratio, and wherein

the antenna-specific signal to be detected is weighted by the weighting coefficient proportional to the reception power only if the signal-to-noise ratio is below a preset threshold value.

5. A method as claimed in claim 1, wherein the method steps are performed substantially at symbol pace.

6. A method as claimed in claim 1, comprising:

dispreading user signals are from the received signal;

generating user-specific channel estimates from the despread user signals;

restoring user signals based on the channel estimates to generate restored user signals;

forming a restored detection signal based on the restored user signals; and

the weighting proportional to the antenna-specific reception power is directed to one or more of the following signals;

a spread signal to be detected, despread user signals, user-specific channel estimates, restored user signals, a restored signal to be detected.

7. A method as claimed in claim 1, wherein the interfering signal is at least partly generated by a second radio system operating in the same frequency band as the radio system.

8. A method as claimed in claim 1, wherein the signal to be detected is a WCDMA signal and the interfering signal is at least partly generated by a second system operating in the same frequency band as the WCDMA system.

9. A receiver in a radio system, comprising:

one or more antennas for receiving a signal including signal components descriptive of a signal to be detected and an interfering signal;

means for measuring the antenna-specific reception power of the received signal, and

means for weighting the signal received in each antenna by a antenna-specific weighting coefficient proportional to the reception power of said signal.

10. A receiver as claimed in claim 9, wherein the antenna-specific weighting coefficient is the reciprocal of the reception power of the signal received in said antenna.

11. A receiver as claimed in claim 9, wherein the receiver is configured to receive the signal using one antenna of the receiver, and the means for weighting are configured to weight the received signal time-dependently by the weighting coefficient proportional to the reception power of the signal.

12. A receiver as claimed in claim 9, comprising:

means for determining the reception power of the signal to be detected;

means for comparing the reception power of the signal to be detected with the reception power of the interfering signal to generate a signal-to-noise ratio, and

the means for weighting are configured to weight the antenna-specific signal to be detected by the weighting coefficient proportional to the reception power only if the signal-to-noise ratio is below a preset threshold value.

13. A receiver as claimed in claim 9, wherein the receiver is configured to perform the weighting substantially at symbol pace.

14. A receiver as claimed in claim 9, the receiver comprising:

means for despreading user signals from the received signals;

means for generating channel estimates from the despread user signals;

means for restoring user signals based on the channel estimates to generate restored user signals; and

means for combining restored user signals to generate a restored signal to be detected, and

the means for weighting are configured to direct a weighting proportional to the antenna-specific reception power to one or more of the following signals;

a spread signal to be detected, despread user signals, user-specific channel estimates, restored user signals, a restored signal to be detected.

15. A receiver as claimed in claim 9, wherein the interfering signal is at least partly generated by a second radio system operating in the same frequency band as the radio system.

16. A receiver as claimed in claim 9, wherein the signal to be detected is a WCDMA signal and the interfering signal is at least partly generated by a second system operating in the same frequency band as the WCDMA system.