Method and system for transmitting and demodulating a communications signal using an adaptive antenna array in a wireless communication system

• US 6,067,324 A
• Filed: 06/30/1998
• Issued: 05/23/2000
• Est. Priority Date: 06/30/1998
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Harrison, Robert Mark
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US09/107,106
• Time in Patent Office: 693 Days
• Field of Search: 375/267, 375/295, 375/347, 375/200, 375/316, 375/358, 375/365, 375/219, 370/522, 370/334, 370/335, 370/342, 455/500, 455/522, 455/517, 455/524, 455/101, 455/73, 455/562, 455/132
• US Class Current: 375/267
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]

Abstract

In a transceiver for transmitting a communication signal from an antenna array in a wireless communications system, a different element pilot is transmitted from a plurality of antenna elements in an antenna array. Thereafter, transmitter control data based upon measured characteristics of the element pilots as measured at a subscriber unit is received at the transceiver. In response to the transmitter control data, a plurality of adaptive array weights for modifying a plurality of element communication signals are determined. Next, the transceiver determines that the subscriber unit is ready to receive a communication signal transmitted from the antenna array and weighted according to the plurality of adaptive array weights. In response to determining that the subscriber unit is ready, the transceiver modifies the plurality of element communication signals according to the determined plurality of adaptive array weights.

Claims

1. A method in a transceiver for transmitting a communication signal from an antenna array in a wireless communications system, the method comprising the steps of:

transmitting a different element pilot from a plurality of antenna elements in an antenna array;

receiving transmitter control data based upon measured characteristics of the element pilots as measured at a subscriber unit;

in response to the transmitter control data, determining a plurality of adaptive array weights for modifying a plurality of element communication signals;

determining that the subscriber unit is ready to receive a communication signal transmitted from the antenna array and weighted according to the plurality of adaptive array weights; and

in response to determining that the subscriber unit is ready, modifying the plurality of element communication signals according to the determined plurality of adaptive array weights.

2. The method for transmitting a communication signal from an antenna array according to claim 1 wherein the transmitter control data includes recommended adaptive array weights for modifying the plurality of element communication signals, and wherein the step of determining a plurality of adaptive array weights further includes selecting the recommended adaptive array weights as the plurality of adaptive array weights for modifying a plurality of element communication signals.

3. The method for transmitting a communication signal from an antenna array according to claim 2 wherein the step of determining a plurality of adaptive array weights includes calculating an estimated channel impulse response based upon the transmitter control data.

4. The method for transmitting a communication signal from an antenna array according to claim 1 wherein the transmitter control data includes phases of the different element pilots.

5. The method for transmitting a communication signal from an antenna array according to claim 1 wherein the step of determining that the subscriber unit is ready includes delaying for a period sufficient for the subscriber unit to become ready to receive a communication signal transmitted from the antenna array and weighted according to the plurality of adaptive array weights.

6. The method for transmitting a communication signal from an antenna array according to claim 1 wherein the step of modifying the plurality of element communication signals according to the determined plurality of adaptive array weights includes modifying the phase and gain of the plurality of element communication signals according to the determined plurality of adaptive array weights.

7. The method for transmitting a communication signal from an antenna array according to claim 6 wherein the step of modifying the phase and gain of the plurality of element communication signals according to the determined plurality of adaptive array weights includes filtering the plurality of element communication signals according to the determined plurality of adaptive array weights.

8. A transceiver for transmitting a communication signal from an antenna array in a wireless communications system comprising:

means for transmitting a different element pilot from a plurality of antenna elements in an array;

means for receiving transmitter control data based upon measured characteristics of the element pilots as measured at a subscriber unit;

means for determining a plurality of adaptive array weights for modifying a plurality of element communication signals in response to the transmitter control data;

means for determining that the subscriber unit is ready to receive a communication signal transmitted from the antenna array and weighted according to the plurality of adaptive array weights; and

means for modifying the plurality of element communication signals according to the determined plurality of adaptive array weights in response to determining that the subscriber unit is ready.

9. The transceiver for transmitting a communication signal from an antenna array according to claim 8 wherein the transmitter control data includes recommended adaptive array weights for modifying the plurality of element communication signals, and wherein the means for determining a plurality of adaptive array weights further includes means for selecting the recommended adaptive array weights as the plurality of adaptive array weights for modifying a plurality of element communication signals.

10. The transceiver for transmitting a communication signal from an antenna array according to claim 9 wherein the means for determining a plurality of adaptive array weights includes means for calculating an estimate channel impulse response based upon the transmitter control data.

11. The transceiver for transmitting a communication signal from an antenna array according to claim 8 wherein the transmitter control data includes phases of the different element pilots.

12. The transceiver for transmitting a communication signal from an antenna array according to claim 8 wherein the means for determining that the subscriber unit is ready includes means for delaying for a period sufficient for the subscriber unit to become ready to receive a communication signal transmitted from the antenna array and weighted according to the plurality of adaptive array weights.

13. The transceiver for transmitting a communication signal from an antenna array according to claim 8 wherein the means for modifying the plurality of element communication signals according to the determined plurality of adaptive array weights includes means for modifying the phase and gain of the plurality of element communication signals according to the determined plurality of adaptive array weights.

14. The transceiver for transmitting a communication signal from an antenna array according to claim 13 wherein the means for modifying the phase and gain of the plurality of element communication signals according to the determined plurality of adaptive array weights includes means for filtering the plurality of element communication signals according to the determined plurality of adaptive array weights.

15. A method in a subscriber unit for receiving a communication signal from an antenna array in a wireless communications system, the method comprising the steps of:

measuring characteristics of a plurality of different element pilots at the subscriber unit, wherein each different element pilot is transmitted from one of a plurality of antenna elements in an antenna array coupled to a transceiver;

transmitting to the transceiver transmitter control data based upon measured characteristics of the plurality of different element pilots;

calculating pilot synthesis weights;

combining the measured characteristics of the plurality of different element pilots using the pilot synthesis weights to produce a synthesized pilot; and

demodulating the communication signal using the synthesized pilot.

16. The method in a subscriber unit for receiving a communication signal from an antenna array according to claim 15 wherein the communication signal comprises element communication signals that are each transmitted from one of the plurality of elements in the antenna array, and wherein the pilot synthesis weights are related to adaptive array weights used at the transceiver to modify characteristics of the element communication signals in response to the transmitter control data.

17. The method in a subscriber unit for receiving a communication signal from an antenna array according to claim 15 wherein the step of measuring characteristics of a plurality of different element pilots includes measuring a phase of a plurality of different element pilots.

18. The method in a subscriber unit for receiving a communication signal from an antenna array according to claim 15 wherein the step of measuring characteristics of a plurality of different element pilots includes estimating a channel impulse response of a channel between an antenna element and the subscriber unit.

19. The method in a subscriber unit for receiving a communication signal from an antenna array according to claim 15 further including the steps of:

calculating recommended adaptive array weights for modifying the plurality of element communication signals; and

wherein the step of transmitting to the transceiver transmitter control data includes transmitting to the transceiver recommended adaptive array weights for modifying the plurality of element communication signals.

20. The method in a subscriber unit for receiving a communication signal from an antenna array according to claim 15 wherein the step of combining the measured characteristics of the plurality of different element pilots using the pilot synthesis weights to produce a synthesized pilot includes:

filtering the measured characteristics of the plurality of different element pilots with the pilot synthesis weights to produce filtered results; and

adding the filtered results to produce the synthesized pilot.

21. A subscriber unit for receiving a communication signal from an antenna array in a wireless communications system comprising:

means for measuring characteristics of a plurality of different element pilots at the subscriber unit, wherein each different element pilot is transmitted from one of a plurality of antenna elements in an antenna array coupled to a transceiver;

means for transmitting to the transceiver transmitter control data based upon measured characteristics of the plurality of different element pilots;

means for calculating pilot synthesis weights;

means for combining the measured characteristics of the plurality of different element pilots using the pilot synthesis weights to produce a synthesized pilot; and

means for demodulating the communication signal using the synthesized pilot.

22. The subscriber unit for receiving a communication signal from an antenna array according to claim 21 wherein the communication signal comprises element communication signals that are each transmitted from one of the plurality of elements in the antenna array, and wherein the pilot synthesis weights are related to adaptive array weights used at the transceiver to modify characteristics of the element communication signals in response to the transmitter control data.

23. The subscriber unit for receiving a communication signal from an antenna array according to claim 21 wherein the means for measuring characteristics of a plurality of different element pilots includes means for measuring a phase of a plurality of different element pilots.

24. The subscriber unit for receiving a communication signal from an antenna array according to claim 21 wherein the means for measuring characteristics of a plurality of different element pilots includes means for estimating a channel impulse response of a channel between an antenna element and the subscriber unit.

25. The subscriber unit for receiving a communication signal from an antenna array according to claim 21 further including:

means for calculating recommended adaptive array weights for modifying the plurality of element communication signals; and

wherein the means for transmitting to the transceiver transmitter control data includes means for transmitting to the transceiver recommended adaptive array weights for modifying the plurality of element communication signals.

26. The subscriber unit for receiving a communication signal from an antenna array according to claim 21 wherein the means for combining the measured characteristics of the plurality of different element pilots using the pilot synthesis weights to produce a synthesized pilot includes:

means for filtering the measured characteristics of the plurality of different element pilots with the pilot synthesis weights to produce filtered results; and

means for adding the filtered results to produce the synthesized pilot.