Receiver method and apparatus with complex pilot filter

• US 6,535,496 B1
• Filed: 05/15/2002
• Issued: 03/18/2003
• Est. Priority Date: 05/28/1996
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Tiedemann, Edward G. Jr., Jou, Yu-Cheun, Odenwalder, Joseph P.
• Primary Examiner(s): Patel, Ajit
• Application Number:
  US10/147,020
• Publication Number:
  US 20030039235A1
• Time in Patent Office: 307 Days
• Field of Search: 370/318, 370/328, 370/329, 370/332, 370/335, 370/342, 370/431, 370/441, 370/491, 370/500, 375/130, 375/140, 375/324
• US Class Current: 370/335
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 7/264 for data rate control
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/0048 Walsh
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0059 Convolutional codes
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence

Abstract

Demodulation of a received high rate CDMA wireless signal is obtained by filtering a complex received signal to provide a complex pilot filter signal. The complex pilot filter signal is then used to phase-adjust a set of demodulated subscriber channel signals.

Claims

1. A method for demodulating a received signal comprising:

multiplying the received signal by a complex pseudonoise (PN) code to provide a complex PN-despread signal;

filtering the complex PN-despread signal to provide a complex filtered pilot signal;

multiplying the complex PN-despread signal by a first data demodulation code to provide a first complex demodulated data signal; and

rotating the first complex demodulated data signal in accordance with a complex conjugate of the complex filtered pilot signal to provide a first phase-adjusted data signal.

2. The method of claim 1 wherein said filtering comprises summing the complex PN-despread signal over a predetermined interval.

3. The method of claim 1 wherein said filtering comprises averaging the complex PN-despread signal.

4. The method of claim 1 wherein said first data demodulation code is a Walsh code.

5. The method of claim 1 further comprising scaling the complex demodulated data signal in accordance with the complex filtered pilot signal.

6. The method of claim 1 further comprising summing the first phase-adjusted data signal over a predetermined number of modulation symbols.

7. The method of claim 6 wherein said predetermined number is 384.

8. The method of claim 1 further comprising:

multiplying the complex PN-despread signal by a second data demodulation code to provide a second complex demodulated data signal; and

rotating the second complex demodulated data signal in accordance with a complex conjugate of the complex filtered pilot signal to provide a second phase-adjusted data signal.

9. The method of claim 8 wherein said first data demodulation code is a first Walsh code, and wherein said second data demodulation code is a second Walsh code that is orthogonal to said first Walsh code.

10. The method of claim 1 wherein the first phase-adjusted data signal comprises power control data.

11. The method of claim 1 wherein the first phase-adjusted data signal comprises BPSK data.

12. The method of claim 1 wherein the first phase-adjusted data signal comprises QPSK data.

13. A wireless receiver for demodulating a received signal, the wireless receiver comprising:

means for multiplying the received signal by a complex pseudonoise (PN) code to provide a complex PN-despread signal;

means for filtering the complex PN-despread signal to provide a complex filtered pilot signal;

first means for multiplying the complex PN-despread signal by a first data demodulation code to provide a first complex demodulated data signal; and

first means for rotating the first complex demodulated data signal in accordance with a complex conjugate of the complex filtered pilot signal to provide a first phase-adjusted data signal.

14. The wireless receiver of claim 13 wherein said means for filtering comprises means for summing the complex PN-despread signal over a predetermined interval.

15. The wireless receiver of claim 13 wherein said means for filtering comprises means for averaging the complex PN-despread signal.

16. The wireless receiver of claim 13 wherein said first means for multiplying is configured to utilize a Walsh code as said first data demodulation code.

17. The wireless receiver of claim 13 further comprising means for scaling the complex demodulated data signal in accordance with the complex filtered pilot signal.

18. The wireless receiver of claim 13 further comprising means for summing the first phase-adjusted data signal over a predetermined number of modulation symbols.

19. The wireless receiver of claim 18 wherein said predetermined number is 384.

20. The wireless receiver of claim 13 further comprising:

second means for multiplying the complex PN-despread signal by a second data demodulation code to provide a second complex demodulated data signal; and

second means for rotating the second complex demodulated data signal in accordance with a complex conjugate of the complex filtered pilot signal to provide a second phase-adjusted data signal.

21. The wireless receiver of claim 20 wherein said first means for multiplying is configured to utilize a first Walsh code as said first data demodulation code, and wherein said second means for multiplying is configured to utilize a second Walsh code as said second data demodulation code, wherein said second Walsh code is orthogonal to said first Walsh code.

22. A wireless receiver for demodulating a received signal, the wireless receiver comprising:

complex pseudonoise (PN) despreader configured to multiply the received signal by a PN code to provide a complex PN-despread signal having an in-phase PN-despread component and a quadrature-phase PN-despread component;

in-phase pilot filter configured to filter the in-phase PN-despread component to provide an in-phase filtered pilot signal;

quadrature-phase pilot filter configured to filter the quadrature-phase PN-despread component to provide a quadrature-phase filtered pilot signal;

first in-phase data code multiplier configured to multiply the in-phase PN-despread component by a first data demodulation code to provide an in-phase demodulated component;

first quadrature-phase data code multiplier configured to multiply the quadrature-phase PN-despread component by said first data demodulation code to provide a quadrature-phase demodulated component;

first in-phase phase-adjustment multiplier configured to multiply the in-phase filtered pilot signal by the in-phase demodulated component to provide a first in-phase phase-adjusted component;

first quadrature-phase phase-adjustment multiplier configured to multiply the quadrature-phase filtered pilot signal by the quadrature-phase demodulated component to provide a first quadrature-phase phase-adjusted component;

summer configured to add the first in-phase phase-adjusted component to the first quadrature-phase phase-adjusted component to provide a first phase-adjusted data signal.

23. The wireless receiver of claim 22 further comprising:

in-phase summer configured to sum said in-phase PN-despread component over a predetermined number of demodulation chips; and

quadrature-phase summer configured to sum said quadrature-phase PN-despread component over said predetermined number of demodulation chips.

24. The wireless receiver of claim 22 wherein said in-phase pilot filter is further configured to average the in-phase PN-despread component to provide the in-phase filtered pilot signal, and wherein said quadrature-phase pilot filter is further configured to average the quadrature-phase PN-despread component to provide the quadrature-phase filtered pilot signal, and wherein.

25. The wireless receiver of claim 22 wherein said first data demodulation code is a Walsh code.

26. The wireless receiver of claim 22 further comprising a data summer configured to sum the first phase-adjusted data signal over a predetermined number of modulation symbols.

27. The wireless receiver of claim 22 wherein said predetermined number is 384.

28. The wireless receiver of claim 22 further comprising:

second in-phase data code multiplier configured to multiply the in-phase PN-despread component by a second data demodulation code to provide an in-phase demodulated component;

second quadrature-phase data code multiplier configured to multiply the quadrature-phase PN-despread component by said second data demodulation code to provide a quadrature-phase demodulated component;

second in-phase phase-adjustment multiplier configured to multiply the in-phase filtered pilot signal by the in-phase demodulated component to provide a second in-phase phase-adjusted component;

second quadrature-phase phase-adjustment multiplier configured to multiply the quadrature-phase filtered pilot signal by the quadrature-phase demodulated component to provide a second quadrature-phase phase-adjusted component;

summer configured to add the second in-phase phase-adjusted component to the second quadrature-phase phase-adjusted component to provide a second phase-adjusted data signal.

29. The wireless receiver of claim 22 wherein said first data demodulation code is a first Walsh code, and wherein said second data demodulation code is a second Walsh code that is orthogonal to said first Walsh code.

30. The wireless receiver of claim 22 further comprising:

second in-phase data code multiplier configured to multiply the in-phase PN-despread component by a second data demodulation code to provide an in-phase demodulated component;

second quadrature-phase data code multiplier configured to multiply the quadrature-phase PN-despread component by said second data demodulation code to provide a quadrature-phase demodulated component;

second in-phase phase-adjustment multiplier configured to multiply the in-phase filtered pilot signal by the quadrature-phase demodulated component to provide a second in-phase phase-adjusted component;

second quadrature-phase phase-adjustment multiplier configured to multiply the quadrature-phase filtered pilot signal by the in-phase demodulated component to provide a second quadrature-phase phase-adjusted component;

summer configured to subtract the second quadrature-phase phase-adjusted component from the second quadrature-phase phase-adjusted component to provide a second phase-adjusted data signal.

31. The wireless receiver of claim 30 wherein said first data demodulation code is a first Walsh code, and wherein said second data demodulation code is a second Walsh code that is orthogonal to said first Walsh code.