Stream transmission method and device

• US 7,133,461 B2
• Filed: 12/14/2001
• Issued: 11/07/2006
• Est. Priority Date: 12/14/2001
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Vook, Frederick W., Thomas, Timothy A.
• Primary Examiner(s): Bayard, Emmanuel
• Assistant Examiner(s): Williams, Lawrence B.
• Application Number:
  US10/017,444
• Publication Number:
  US 20030112889A1
• Time in Patent Office: 1,789 Days
• Field of Search: 375/231, 375/295, 375/347, 375/260, 375/299, 455/138, 455/562.1, 370/210
• US Class Current: 375/295
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A transmitter for implementing a stream transmission method is disclosed. Optionally, the transmitter first determines an equal weighting of a plurality of stream weights and transmits a plurality of transmission signals as a function of a plurality of data streams and the equal weighting of the plurality of stream weights. Thereafter, the transmitter reiterates as needed a determination of an unequal weighting of the plurality of stream weights and a transmission of the plurality of transmission signals as a function of the plurality of data streams and the unequal weighting of the plurality of stream weights.

Claims

1. A method of operating a transmitter, said method comprising:

(1) being provided an average over at least one realization of a channel vector wherein elements of the channel vector are random variables;

(2) determining a mean square error for each stream weight of a plurality of stream weights based on the average over at least one realization of a channel vector;

(3) determining a first stream weight of the plurality of stream weights having the largest mean square error;

(4) increasing a power of the first stream weight;

(5) decreasing a power of each stream weight of the plurality of stream weights excluding the first stream weight; and

repeating steps (2) through (5) when all of the mean square errors of the plurality of stream weights are unequal.

2. The method of claim 1, further comprising:

establishing an increment,

wherein an increasing of the power of the first stream weight is by a summation of the power and the increment.

3. A method of operating a transmitter, said method comprising:

(1) initializing a first stream weight;

(2) establishing a resolution value, an initial value of the increment, and a statistical nature of the channel vector;

(3) determining a weighting of a plurality of stream weights excluding the first stream weight;

(4) determining a power variable;

(5) increasing the first stream weight by a product of the power variable and an increment;

(6) dividing the increment by a factor subsequent to increasing the first stream weight by a product of the power variable and the increment;

(7) determining a weighting of a plurality of stream weights excluding the first stream weight; and

repeating steps 4–

7 when the increment is greater than the resolution value.

4. A transmitter, comprising:

a module operable to determine a first unequal weighting of a plurality of stream weights;

means for transmitting a plurality of transmission signals as a function of a plurality of data streams and the first unequal weighting of the plurality of streams weights;

wherein, to determine the first unequal weighting of the plurality of stream weights, said module is further operable to;

(1) determine a mean square error for each stream weight of a plurality of stream weights;

(2) determine a first stream weight of the plurality of stream weights having the largest mean square error;

(3) increase a power of the first stream weight; and

(4) decrease a power of each stream weight of the plurality of stream weights excluding the first stream weight and

repeat steps (1) through (4) when all of the mean square errors of the plurality of stream weights are unequal.

5. The transmitter of claim 4, wherein:

said module is operable to determine a second unequal weighting of the plurality of stream weights subsequent to the determination of the first unequal weighting for the plurality of stream weights; and

the plurality of transmission signals are transmitted as a function of the plurality of data streams and the second unequal weighting of the plurality of streams weights.

6. The transmitter of claim 4, wherein, to determine the first unequal weighting of the plurality of stream weights, said module is further operable to:

establish a set of statistics corresponding to a channel vector.

7. The transmitter of claim 4, wherein, to determine the first unequal weighting of the plurality of stream weights, said module is further operable to:

establish an increment.

8. The transmitter of claim 7, wherein an increase in the power of the first stream weight is by a summation of the power and the increment.

9. The transmitter of claim 4, wherein, to determine a first unequal weighting of the plurality of stream weights, said module is further operable to:

initialize a first stream weight; and

increase the first stream weight by a product of a power variable and an increment.

10. A method of transmitting a plurality of data streams from a transmitter with multiple transmit antennas to a receiving unit, the method comprising the steps of:

weighting data streams by unequal power weightings to create a plurality of weighted data streams, wherein the unequal power weightings for each data stream is based on a noise power and an average over at least one realization of a channel vector, wherein elements of the channel vector are random variables; and

transmitting the plurality of weighted data streams to a receiving unit.

11. The method of claim 10 wherein the step of transmitting the plurality of weighted data streams involves transmitting the multiple data streams over multiple subcarriers.

12. The method of claim 10 wherein the random variables are independent complex Gaussian random variables.

13. The method of claim 10 further comprising the steps of:

being provided the noise power; and

determining the unequal power weighting for each data stream.

14. The method of claim 13 wherein the step of determining the unequal power weighting for each data stream involves determining unequal power weightings so that a stream decoding order of successive cancellation performed at the receiving unit is predetermined.

15. The method of claim 13 wherein the step of determining the unequal power weighting for each data stream involves determining unequal power weightings so that a mean squared error of each data stream after successive cancellation at the receiving unit is substantially equal.

16. The method of claim 13 wherein the step of being provided the noise power involves the receiving unit feeding back the noise power.

17. The method of claim 13 wherein the step of determining the unequal power weighting is performed at the receiving unit and the receiving unit provides the unequal power weights to the transmitter.