System and Method for Joint Maximal Ratio Combining Using Time-Domain Based Signal Processing

• US 20030165187A1
• Filed: 07/18/2002
• Published: 09/04/2003
• Est. Priority Date: 03/01/2002
• Status: Active Grant

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: Cognio, Inc. (Cisco Systems, Inc.)
• Inventors: Tesfai, Yohannes, Vaidyanathan, Chandra, Sugar, Gary L.
• Granted Patent: US 6,873,651 B2
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• 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: H04L 1/06 using space diversity
• CPC Class Codes: H04L 2025/03445 Time domain
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Abstract of Disclosure

A spatial signal processing system and method are provided to optimize the received signal-to-noise ratio (SNR) at a first radio communication device based on the transmit filter at another radio communication device. Using an estimate of the channel derived from a signal received at one device from another device, an iterative process is provided to determine complex weights for one or more tapped delay-line transmit filters at each of two communication devices that optimize the received SNR.

Claims

1. A method for communicating signals between a first communication device and a second communication device using radio frequency (RF) communication techniques, comprising:

2. The method of claim 1, wherein the step of generating the transmit filter vector at the first communication device further comprises normalizing each sub-vector of the transmit filter vector so that the total power associated with a transmitted signal is divided equally among the plurality of antennas of the first communication device.

3. The method of claim 1, wherein the step of deriving the one or more transmit filter sub-vectors for the second communication device comprises equating each transmit filter sub-vector to the corresponding sub-vector of the principal eigenvector.

4. The method of claim 1, wherein the step of deriving the one or more transmit filter sub-vectors at the second communication device further comprises computing the norm of each of a plurality of sub-vectors of the principal eigenvector and dividing each sub-vector of the principal eigenvector by the norm and by the square root of the number of plurality of antennas of the second communication device so that the power of the signal transmitted by the second communication device is divided equally among the plurality of antennas of the first communication device.

5. The method of claim 1, and further comprising at the first communication device steps of:

6. The method of claim 5, and further comprising repeating steps (iii) through (v) at the first communication device and steps (i) through (iv) at the second communication device for signals transmitted between the first and second communication devices, to converge to transmit filter vectors at the first and second communication devices that optimize the signal-to-noise ratio of signals communicated between them.

7. The method of claim 5, wherein the step of updating the transmit filter sub-vectors of the first communication device comprises equating each transmit filter sub-vector to the corresponding sub-vector of the principal eigenvector computed by the first communication device.

8. The method of claim 5, wherein the step of updating the transmit filter sub-vectors of the first communication device comprises computing the norm of each of a plurality of sub-vectors of the principal eigenvector and dividing each sub-vector of the principal eigenvector by the norm and by the square root of the number of plurality of antennas of the first communication device.

9. A method for radio communication between a first communication device and a second communication device, comprising:

10. The method of claim 9, wherein the step of updating comprises equating each transmit filter sub-vector to the corresponding sub-vector of the principal eigenvector.

11. The method of claim 9, wherein the step of updating further comprises computing the norm of each of a plurality of sub-vectors of the principal eigenvector and dividing each sub-vector of the principal eigenvector by the norm and by the square root of the number of plurality of antennas of the first communication device so that the power of the signal transmitted by the first communication device is divided equally among the plurality of antennas of the first communication device.

12. The method of claim 9, and further comprising repeating steps (c) through (e) for each signal received at the first communication device from the second communication device to update the transmit filter vector at the first communication device for transmission of signals from the first communication device to the second communication device.

13. A medium encoded with instructions that, when executed, perform a method comprising the steps of:

14. The medium of claim 13, wherein the instructions encoded on the medium for performing the step of updating comprises instructions for equating each transmit filter sub-vector to the corresponding sub-vector of the principal eigenvector.

15. The medium of claim 13, wherein the instructions encoded on the medium for performing the step of updating further comprise instructions that compute the norm of each of a plurality of sub-vectors of the principal eigenvector and divide each sub-vector of the principal eigenvector by the norm and by the square root of the number of plurality of antennas of the first communication device so that the power of the signal transmitted by the first communication device is divided equally among the plurality of antennas of the first communication device.

16. The medium of claim 13, and further comprising instructions that repeat steps (c) through (d) for each signal received at the first communication device from the second communication device to update the transmit filter vector at the first communication device for transmission of signals from the first communication device to the second communication device.

17. The medium of claim 13, wherein the instructions associated with the computations of steps (a) through (e) are implemented by one or more arrays of gates.

18. The medium of claim 13, wherein the instructions are processor readable instructions, that when executed by a processor, cause the processor to perform steps (a) through (e).

19. A communication device comprising the medium of claim 13, and further comprising:

20. A semiconductor device comprising a plurality of gates configured to implement:

21. The semiconductor device of claim 20, wherein the computation blocks update the plurality of transmit sub-vectors by equating each transmit filter sub-vector to the corresponding sub-vector of the principal eigenvector.

22. The semiconductor device of claim 20, wherein the computation blocks updates the plurality of transmit sub-vectors by computing the norm of each of a plurality of sub-vectors of the principal eigenvector and dividing each sub-vector of the principal eigenvector by the norm and by the square root of the number of the plurality of antennas so that the power of the signal transmitted is divided equally among the plurality of antennas.

23. A radio communication device comprising the semiconductor device of claim 20, and further comprising: