Method and system in a transceiver for controlling a multiple-input, multiple-output communications channel

• US 20030185309A1
• Filed: 04/01/2002
• Published: 10/02/2003
• Est. Priority Date: 04/07/2001
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Harrison, Robert M., Rohani, Kamyar, Pautler, Joseph J.
• Granted Patent: US 6,859,503 B2
• Time in Patent Office: Days
• US Class Current: 375/257
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0443 utilizing "waterfilling" technique
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04B 7/0842 Weighted combining
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 2025/03802 Signalling on the reverse channel
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/021 Estimation of channel covariance
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 25/0248 Eigen-space methods
• CPC Class Codes: H04L 25/03159 operating in the frequency domain H04L25/03165, H04L25/03178 take precedence

Abstract

The present invention makes it possible to increase a data rate between a transmitter and receiver using a multiple-input, multiple-output radio frequency channel. A multiple-stream, multiple-antenna receiver measures a composite channel between a multiple-antenna transmitter and a multiple-antenna receiver to produce a composite channel measurement. The receiver selects a plurality of antenna array weight sets for use in the multiple-antenna transmitter in response to the composite channel measurement, where each antenna array weight set is associated with one of multiple data streams. Information describing the plurality of antenna array weight sets for use in the multiple-antenna transmitter are then transmitted.

Claims

1. A feedback method in a multiple-stream, multiple-antenna receiver, the method comprising the steps of:

measuring a composite channel between a multiple-antenna transmitter and a multiple-antenna receiver to produce a composite channel measurement;

selecting a plurality of antenna array weight sets for use in the multiple-antenna transmitter in response to the composite channel measurement, wherein each antenna array weight set is associated with one of multiple data streams; and

transmitting information describing the plurality of antenna array weight sets for use in the multiple-antenna transmitter.

2. The feedback method of claim 1, wherein the step of selecting a plurality of antenna array weight sets further includes selecting a plurality of antenna array weight sets having a cross correlation less than the inverse of a number of antenna elements in the antenna array of the multiple-antenna transmitter.

3. The feedback method of claim 1 further including the steps of:

selecting a data rate for each data stream in response to the composite channel measurement; and

transmitting information describing the data rate selection for use in the multiple-antenna transmitter.

4. The feedback method of claim 1 further including the steps of transmitting information used to describe a quality of each data stream for use in the multi-antenna transmitter.

5. The feedback method of claim 1 wherein the step of transmitting information describing the plurality of antenna array weight sets further includes transmitting a first amount of information describing a first antenna array weight set and transmitting a second amount of information describing a second antenna array weight set, wherein the second amount of information is less than the first amount of information.

6. The feedback method of claim 1 wherein the step of selecting the plurality of antenna array weight sets further includes the steps of:

selecting a first antenna array weight set from a codebook having a plurality of preselected antenna array weight sets; and

selecting a second antenna array weight set from a subset of the codebook.

7. The feedback method of claim 6 wherein the step of transmitting information describing the plurality of antenna array weight sets further includes the steps of:

transmitting a first amount of information describing a first antenna array weight set; and

transmitting a second amount of information describing a second antenna array weight set, wherein the second amount of information is less than the first amount of information.

8. The feedback method of claim 7 wherein the steps of transmitting a first amount of information describing a first antenna array weight set and transmitting a second amount of information describing a second antenna array weight set further includes jointly encoding the first and second amount of information.

9. The feedback method of claim 1 further including the step of transmitting information needed to set data rates of each data stream in the multiple-antenna transmitter.

10. The feedback method of claim 1 further including the step of transmitting information needed to set a relative transmit power of each data stream in the multiple-antenna transmitter.

11. The feedback method of claim 1 further including the steps of:

measuring a composite channel between a multiple-antenna transmitter and a multiple-antenna receiver to produce a composite channel measurement, wherein pilot signals are received from M number of available antennas at the multiple-antenna transmitter;

selecting N antennas to be used at the transmitter, from M number of available antennas, in response to the composite channel measurement, wherein the N selected antennas will be used to form the antenna array at the multiple-antenna transmitter.

12. A feedback method in a multiple-stream, multiple-antenna transmitter, the method comprising the steps of:

splitting user data to produce multiple data streams;

transmitting a pilot signal from each antenna of an antenna array;

receiving indications of a selected antenna array weight set for each of the multiple data streams, wherein each antenna array weight set includes weights associated with each antenna of the antenna array;

using the selected antenna array weight sets, weighting each data stream to produce antenna signals for each antenna in the antenna array; and

transmitting the antenna signals, wherein the multiple data streams are transmitted.

13. The feedback method of claim 12 further including the steps of:

encoding and modulating each of multiple data stream to produce modulated data streams; and

using the selected antenna array weight sets, weighting each modulated data stream to produce antenna signals for each antenna in the antenna array.

14. The feedback method of claim 12 further including the steps of:

receiving indications of a selected data rate for each data stream;

splitting data in proportion to the selected data rates for each data stream; and

transmitting multiple data streams using the selected data rates for each data stream.

15. The feedback method of claim 14 further including the steps of:

selecting encoding and modulation schemes for each data stream in response to the selected data rate; and

transmitting multiple data streams using the selected encoding and modulation schemes for each data stream.

16. A feedback method in a multiple-stream, multiple-antenna transceiver having a multiple-antenna transmitter and a multiple-antenna receiver, the method comprising the steps of:

splitting user data to produce multiple data streams;

in the multiple-antenna transmitter, transmitting a pilot signal from each antenna of an antenna array;

using the pilot signals from each antenna of the antenna array, measuring a composite channel between the multiple-antenna transmitter and the multiple-antenna receiver to produce a composite channel measurement;

selecting a plurality of antenna array weight sets for use in the multiple-antenna transmitter in response to the composite channel measurement, wherein each antenna array weight set is associated with one of multiple data streams;

transmitting, from the multiple-antenna receiver to the multiple-antenna transmitter, information describing the plurality of antenna array weight sets;

in the multiple-antenna transmitter, receiving information describing a selected antenna array weight set for each of the multiple data streams, wherein each antenna array weight set includes weights associated with each antenna of the antenna array; and

encoding and modulating each of the multiple data streams to produce modulated data streams;

using the selected antenna array weight sets, weighting each modulated data stream to produce antenna signals for each antenna in the antenna array; and

transmitting multiple data streams using the selected antenna array weight set for each data stream, wherein each data stream has a different antenna pattern.