Multiple input, multiple output system and method

• US 20030210750A1
• Filed: 05/13/2002
• Published: 11/13/2003
• Est. Priority Date: 05/01/2001
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Onggosanusi, Eko N., Dabak, Anand G.
• Granted Patent: US 7,801,247 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0212 of impulse response
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/0242 using matrix methods

Abstract

A linear transformation of parallel multiple input, multiple output (MIMO) encoded streams; also, space-time diversity and asymmetrical symbol mapping of parallel streams. Separately or together, these improve error rate performance as well as system throughput. Preferred embodiments include CDMA wireless systems with multiple antennas.

Claims

1. A method of transmitting, comprising:

(a) providing encoded streams x₁, x₂, . . . , x_p with P an integer greater than 1;

(b) linearly transforming said x₁, x₂, . . . , x_{p x} into y₁, y₂, . . . , y_p and

(c) transmitting said y₁, y₂, . . . , y_P.

(d) wherein said linearly transforming of step (b) derives from transmission channel coefficients.

2. The method of claim 1, wherein:

(a) said linear transforming of step (b) of claim 1 is selection from a finite set of linear transformations.

3. The method of claim 1, wherein:

(a) said linear transforming of step (b) of claim 1 is with parameters provided by a recipient of said transmitting of step (c) of claim 1.

4. The method of claim 3, wherein:

(a) said recipient provides said parameters via a feedback channel.

5. The method of claim 1, wherein:

(a) said linear transforming of step (b) of claim 1 is with parameters derived from receipt of signals from a recipient of said transmitting of step (c) of claim 1.

6. The method of claim 5, further comprising:

(a) transmitting said parameters to said recipient via a signaling channel.

7. The method of claim 1, wherein:

(a) said linear transforming of step (b) of claim 1 is with parameters arising from transforming a channel from a recipient of said transmitting of step (c) of claim 1, said transforming a channel approximates an independent, identically distributed or uncorrelated channel.

8. The method of claim 1, wherein:

(a) said linear transforming of step (b) of claim 1 is with a P×

P matrix W determined by combinations of estimations of E[(Wh_p)* Wh_p′

] approximating a multiple of the P×

P identity matrix where h_p are coefficients of a channel to a recipient of said transmitting of step (c) of claim 1.

9. The method of claim 8, wherein:

(a) the elements of W are quantized.

10. The method of claim 8, wherein:

(a) said coefficient of a channel are estimated with pilot symbols from said recipient.

11. The method of claim 1, further comprising:

(a) spreading said y₁, y₂, . . . , y_p prior to transmission.

12. A method of receiving, comprising:

(a) treating received signals as a linear transform of P parallel encoded signals from P antennas, with P an integer greater than 1;

(b) providing said linear transform;

(c) detecting said signals using said linear transform applied to channel coefficient estimates.

13. The method of claim 12, wherein:

(a) said step (c) of claim 12 is an interference resistant detecting.

14. The method of claim 12, wherein:

(a) said step (c) of claim 12 is an iterative minimum mean square error detecting.

15. The method of claim 12, wherein:

(a) said received signals of step (a) of claim 12 is with Q antennas, with Q an integer greater than 1.

16. The method of claim 12, wherein:

(a) said receiving of step (a) of claim 12 is with 1 antenna.

17. The method of claim 12, wherein:

(a) said linear transform of step (b) of claim 12 is with parameters provided by a source of said signals of step (a) of claim 12.

18. The method of claim 12, wherein:

(a) said linear transform of step (b) of claim 12 is with parameters derived from channel estimates using second signals from a source of said signals of claim 12 step (a).

19. The method of claim 12 wherein:

(a) said linear transform of step (b) of claim 12 is with a P×

P matrix W determined by combinations of estimations of E[(Wh_p)* Wh_p′

] approximating a multiple of the P×

P identity matrix where h_p are coefficients of a channel of said received signals of step (a) of claim 12.

20. The method of claim 12, wherein:

(a) said treating of step (a) of claim 12 includes resolving multiple signal paths; and

(b) said detecting of step (c) of claim 12 includes multipath interference suppression.

21. A transmitter, comprising:

(a) a serial-to-parallel converter coupled to a data stream,

(b) a linear transformer coupled to said serial-to-parallel converter; and

(c) transmit antennas couple to said linear transformer.

22. A receiver, comprising:

(a) a channel coefficient estimator;

(b) a linear transformation source coupled to said estimator; and

(c) a detector coupled to said estimator and said linear transformation source.