Interference cancellation method in radio system

• US 7,450,671 B2
• Filed: 12/18/2002
• Issued: 11/11/2008
• 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
• Primary Examiner(s): Tran; Khai
• Application Number:
  US10/321,712
• Publication Number:
  US 20030176169A1
• Time in Patent Office: 2,155 Days
• Field of Search: 375/347, 375/316, 375/267, 375/148, 455/562.1
• US Class Current: 375/347
• 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, comprising:

receiving a signal including signal components descriptive of a signal to be detected and an interfering signal;

measuring an antenna-specific reception power of the received signal; and

weighting the received signal by an antenna-specific weighting coefficient proportional to the reception power of said signal.

wherein the antenna-specific weighting coefficient is the reciprocal of the reception power of the signal.

2. A method as claimed in claim 1, wherein the received signal is weighted time-dependently by the weighting coefficient proportional to the reception power of the signal.

3. A method as claimed in claim 1, further 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,

wherein an 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.

4. A method as claimed in claim 1, wherein the method is performed substantially at symbol pace.

5. 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.

6. A method as claimed in claim 1, wherein the signal to be detected is a wideband code division multiple access signal and the interfering signal is at least partly generated by a second system operating in the same frequency band as the wideband code division multiple access system.

7. A method, 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 an antenna-specific reception power of the received signal;

weighting the received signal by a weighting coefficient proportional to the reception power of said signal;

despreading user signals 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; and

forming a restored detection signal based on the restored user signals,

wherein 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.

8. An apparatus, comprising:

a receiver configured to receive a signal including signal components descriptive of a signal to be detected and an interfering signal;

a measuring unit configured to measure an antenna-specific reception power of the received signal; and

a weighting unit configured to weight the received signal by an antenna-specific weighting coefficient proportional to the reception power of said signal,

wherein the antenna-specific weighting coefficient is the reciprocal of the reception power of the received signal.

9. An apparatus as claimed in claim 8, wherein the weighting unit is configured to weight the received signal time-dependently by the weighting coefficient proportional to the reception power of the signal.

10. An apparatus as claimed in claim 8, comprising:

determining unit configured to determine the reception power of the signal to be detected; and

comparing unit configured to compare the reception power of the signal to be detected with the reception power of the interfering signal to generate a signal-to-noise ratio,

wherein the weighting unit is further 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.

11. An apparatus as claimed in claim 8, wherein the apparatus is configured to perform the weighting substantially at symbol pace.

12. An apparatus as claimed in claim 8, wherein the interfering signal is at least partly generated by a second radio system operating in the same frequency band as the radio system.

13. An apparatus as claimed in claim 8, wherein the signal to be detected is a wideband code division multiple access signal and the interfering signal is at least partly generated by a second system operating in the same frequency band as the wideband code division multiple access system.

14. The apparatus as claimed in claim 8, wherein the apparatus is a receiver.

15. An apparatus, comprising:

a receiver configured to receive a signal including signal components descriptive of a signal to be detected and an interfering signal;

a measuring unit configured to measure an antenna-specific reception power of the received signal;

a weighting unit configured to weight the received signal by an antenna specific weighting coefficient proportional to the reception power of said signal;

a despreading unit configured to despread user signals from the received signals;

a generator configured to generate channel estimates from the despread user signals;

a restoring unit configured to restore user signals based on the channel estimates to generate restored user signals; and

a combining unit configured to combine restored user signals to generate a restored signal to be detected,

wherein the weighting unit is further 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.

16. The apparatus as claimed in claim 15, wherein the apparatus is a receiver.

17. An apparatus, comprising:

receiving means for receiving a signal including signal components descriptive of a signal to be detected and an interfering signal in a radio system;

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

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

wherein the antenna-specific weighting coefficient is the reciprocal of the reception power of the received signal.

18. A computer program embodied on a computer-readable medium comprising computer code for causing a computer to perform a method for receiving a signal in a radio system, the method comprising:

receiving a signal including signal components descriptive of a signal to be detected and an interfering signal;

measuring an antenna-specific reception power of the received signal; and

weighting the received signal by a weighting coefficient proportional to the reception power of said signal,

wherein the antenna-specific weighting coefficient is the reciprocal of the reception power of the received signal.

19. An apparatus, comprising:

at least one receiver configured to receive a signal including signal components descriptive of a signal to be detected and an interfering signal;

a measuring unit configured to measure an antenna-specific reception power of the received signal; and

a weighting unit configured to weight the signal received in the receivers by a antenna-specific weighting coefficient proportional to the reception power of said signal,

wherein the antenna-specific weighting coefficient is the reciprocal of the reception power of the signal received in said receiver.

20. The apparatus as claimed in claim 19, wherein the weighting unit is configured to weight the received signal time-dependently by the weighting coefficient proportional to the reception power of the signal.

21. The apparatus as claimed in claim 19, comprising:

a determining unit configured to determine the reception power of the signal to be detected; and

a comparing unit configured to compare the reception power of the signal to be detected with the reception power of the interfering signal to generate a signal-to-noise ratio,

wherein the weighting unit is further 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.

22. An apparatus, comprising:

at least one receiver configured to receive a signal including signal components descriptive of a signal to be detected and an interfering signal;

a measuring unit configured to measure an antenna-specific reception power of the received signal;

a weighting unit configured to weight the signal received in the receivers by a antenna-specific weighting coefficient proportional to the reception power of said signal;

a despreading unit configured to despread user signals from the received signals;

a generator configured to generate channel estimates from the despread user signals;

a restoring unit configured to restore user signals based on the channel estimates to generate restored user signals; and

a combining unit configured to combine restored user signals to generate a restored signal to be detected,

wherein the weighting unit is further 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.

23. An apparatus, comprising:

receiving means for receiving a signal including signal components descriptive of a signal to be detected and an interfering signal;

measuring means for measuring an reception power of the received signal; and

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

wherein the antenna-specific weighting coefficient is the reciprocal of the reception power of the signal received in said receiving means.

24. The apparatus as claimed in claim 23, wherein the weighting means is configured for weighting the received signal time-dependently by the weighting coefficient proportional to the reception power of the signal.

25. An apparatus, comprising:

receiving means for receiving a signal including signal components descriptive of a signal to be detected and an interfering signal;

measuring means for measuring an antenna-specific reception power of the received signal;

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

dispreading means for despreading user signals from the received signals;

generating means for generating channel estimates from the despread user signals;

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

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

wherein the weighting means is further 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.