System and method for received signal prediction in wireless communications system

• US 7,433,384 B2
• Filed: 01/09/2006
• Issued: 10/07/2008
• Est. Priority Date: 05/17/2001
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Smee, John Edward, Sindhushayana, Nagabhushana
• Primary Examiner(s): Ha; Dac V
• Application Number:
  US11/328,590
• Publication Number:
  US 20060120439A1
• Time in Patent Office: 1,002 Days
• Field of Search: 375/142, 375/143, 375/150, 375/152, 375/260, 375/267, 375/347, 375/349, 375/363, 370/321, 370/334, 370/337, 370/347, 455/132, 455/136, 455/137, 455/269, 455/273, 455/276.1, 455/278.1, 455/296
• US Class Current: 375/142
• CPC Class Codes: H04B 1/71055 using minimum mean squared error [MMSE] detector
• CPC Class Codes: H04B 7/0848 Joint weighting
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Method and apparatus to compute the combiner coefficients for wireless communication systems for a space-time solution. One embodiment trains the weights on a signal known a priori that is time multiplexed with other signals, such as a pilot signal in a High Data Rate, HDR, system, wherein the signal is transmitted at full power. A Minimizing Mean Square Error, MMSE, approach is applied allowing weight combining on a per path basis. The weights are calculated as a function of a noise correlation matrix and spatial signature per path. The noise correlation matrix is determined from an autocorrelation matrix of the received signal. In one embodiment, the MMSE approach is applied to a non-time gated pilot signal.

Claims

1. In a wireless communication system having a plurality of receive antennas and a combiner for combining signals received on the plurality of receive antennas, a method for determining combiner weights applied in the combiner, comprising:

receiving a first signal at a first antenna of the plurality of receive antennas, the first signal including a pilot signal and at least one concurrently transmitted traffic signal;

receiving a second signal at a second antenna of the plurality of receive antennas, the second signal including the pilot signal and the at least one concurrently transmitted traffic signal; and

determining a first weight in the combiner based on the first and second signals and a relative energy of the pilot signal to the at least one concurrently transmitted traffic signal, the first weight associated with the first and second signals.

2. The method of claim 1, wherein determining a first weight further comprises:

determining a cross correlation of the plurality of receive antennas.

3. The method of claim 2, wherein determining a first weight further comprises:

computing a signal expectation value for each of the plurality of receive antennas.

4. The method of claim 3, wherein determining a first weight further comprises:

determining an autocorrelation matrix for the received signal.

5. The method of claim 4, wherein determining a first weight further comprises:

computing a noise correlation for the received signal as a function of the autocorrelation matrix of the received signal and a spatial signature; and

computing a weight associated with the first and second signals.

6. The method of claim 1, wherein the second signal corresponds to a multipath.

7. The method of claim 1, wherein the determining further comprises:

estimating information received in the first signal and the second signal by minimizing a mean square error with respect to the information as transmitted.

8. The method of claim 1, wherein at least a part of the first and second signals are known a priori.

9. The method of claim 8, wherein the first and second signals are received during a pilot signal interval.

10. The method of claim 9, wherein the system employs spread spectrum transmissions.

11. The method of claim 1 , wherein interference associated with different paths are assumed uncorrelated on all antennas, and wherein interference associated with a same path are assumed correlated across different antennas.

12. The method of claim 1 embodied on a computer readable media.

13. A method for communication in a wireless communication system, comprising:

receiving information including a pilot signal and at least one concurrently transmitted traffic signal via a first communication path;

receiving the information including the pilot signal and the at least one concurrently transmitted traffic signal via a second communication path; and

estimating information based on a relative energy of the pilot signal to the at least one concurrently transmitted traffic signal from the first communication path using information received from the second communication path.

14. The method of claim 13, wherein estimating further comprises:

determining a first estimate of the information from the first communication path;

determining a second estimate of the information from the second communication path; and

determining a third estimate of the information as a function of the first and second estimates.

15. A remote station apparatus comprising:

means for receiving information including a pilot signal and at least one concurrently transmitted traffic signal via a first communication path and a second communication path; and

means for generating an estimate of information based on a relative energy of the pilot signal to the at least one concurrently transmitted traffic signal from the first communication path using information received from the second communication path.

16. A remote station apparatus comprising:

a first rake receiver having a plurality of fingers;

a second rake receiver having a plurality of fingers; and

a first path processing unit coupled to one of the plurality of fingers of the first rake receiver and one of the plurality of fingers of the second rake receiver, wherein combiner weights of the first and second rake receivers are at least determined in part from the relative energy of a received pilot signal to at least one concurrently transmitted traffic signal.

17. In a wireless communication system having a plurality of receive antennas and a combiner for combining signals received on the plurality of receive antennas, a method for determining combiner weights applied in the combiner, comprising:

receiving a first signal at a first antenna of the plurality of receive antennas, the first signal including a pilot signal and at least one concurrently transmitted traffic signal; and

determining a first weight in the combiner based on signals and the relative energy of the pilot signal to the at least one concurrently transmitted traffic signal received at the plurality of antennas.

18. A method for determining weights applied in a combiner of a wireless receiver, comprising:

determining a relative energy of a received pilot signal to at least one received traffic signal, wherein the received pilot signal and the at least one received traffic signal are received as first and second signals in a diversity receiver; and

determining a first weight in the combiner based on the relative energy.

19. In a wireless communication system having a plurality of receive antennas and a combiner for combining signals received on the plurality of receive antennas, an apparatus for determining combiner weights applied in the combiner, comprising:

means for receiving a first signal at a first antenna of the plurality of receive antennas, the first signal including a pilot signal and at least one concurrently transmitted traffic signal;

means for receiving a second signal at a second antenna of the plurality of receive antennas, the second signal including the pilot signal and the at least one concurrently transmitted traffic signal; and

means for determining a first weight in the combiner based on the first and second signals and a relative energy of the pilot signal to the at least one concurrently transmitted traffic signal, the first weight associated with the first and second signals.

20. The apparatus of claim 19, wherein the means for determining a first weight further comprises:

means for determining a cross correlation of the plurality of receive antennas.

21. The apparatus of claim 20, wherein the means for determining a first weight further comprises:

means for computing a signal expectation value for each of the plurality of receive antennas.

22. The apparatus of claim 21, wherein the means for determining a first weight further comprises:

means for determining an autocorrelation matrix for the received signal.

23. The apparatus of claim 22, wherein the means for determining a first weight further comprises:

means for computing a noise correlation for the received signal as a function of the autocorrelation matrix of the received signal and a spatial signature; and

means for computing a weight associated with the first and second signals.

24. The apparatus of claim 19, wherein the second signal corresponds to a multipath.

25. The apparatus of claim 19, wherein the means for determining further comprises:

means for estimating information received in the first signal and the second signal by minimizing a mean square error with respect to the information as transmitted.

26. The apparatus of claim 19, wherein at least a part of the first and second signals are known a priori.

27. The apparatus of claim 26, wherein the first and second signals are received during a pilot signal interval.

28. The apparatus of claim 19, wherein the system employs spread spectrum transmissions.

29. The apparatus of claim 19, wherein interference associated with different paths are assumed uncorrelated on all antennas, and wherein interference associated with a same path are assumed correlated across different antennas.

30. A computer program product, comprising:

a computer-readable medium comprising code for causing at least on computer to;

receive a first signal at a first antenna of a plurality of receive antennas, the first signal including a pilot signal and at least one concurrently transmitted traffic signal;

receive a second signal at a second antenna of the plurality of receive antennas, the second signal including the pilot signal and the at least one concurrently transmitted traffic signal; and

determine a first weight in a combiner based on the first and second signals and a relative energy of the pilot signal to the at least one concurrently transmitted traffic signal, the first weight associated with the first and second signals.