METHOD AND APPARATUS FOR SPACE-TIME CODING AND DECODING

• US 20090116375A1
• Filed: 10/25/2007
• Published: 05/07/2009
• Est. Priority Date: 10/25/2006
• Status: Active Grant

• Current Assignee: VID SCALE Inc. (InterDigital, Inc.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Yang, Yuli
• Granted Patent: US 7,675,845 B2
• Time in Patent Office: Days
• US Class Current: 370/208
• CPC Class Codes: H04L 1/0631 Receiver arrangements
• CPC Class Codes: H04L 1/0668 Orthogonal systems, e.g. using Alamouti codes

Abstract

The present invention relates to methods for space-time coding and decoding in a wireless communication system with multiple antennas including: generating an orthogonal matrix according to signals to be transmitted; generating a coefficient matrix corresponding to the orthogonal matrix according to channel status information received; and generating a transmission matrix according to the orthogonal matrix and the coefficient matrix; performing a weight-combination for received signals according to channel status information in a receiver; and obtaining estimations of transmitted signals corresponding to the received signals by performing detection for the received signals. The present invention also provides apparatuses for space-time coding and decoding. By applying the present invention, the bit error rate of a system is reduced and bit error performance of the system is improved. And the transmission rate of the system is increased remarkably when there are more than one complex signals to be transmitted.

Claims

1. A method for space-time coding, comprising:

generating an orthogonal matrix for signals to be transmitted;

generating a coefficient matrix corresponding to the orthogonal matrix according to channel status information; and

generating a transmission matrix according to the orthogonal matrix and the coefficient matrix.

2. The method of claim 1, wherein generating the orthogonal matrix for the signals to be transmitted comprises:

dividing the signals to be transmitted into groups according to the number of transmission antennas in a system; and

generating the orthogonal matrix according to the signals grouped.

3. The method of claim 1, wherein generating the orthogonal matrix for the signals to be transmitted comprises:

generating an M×

M orthogonal matrix X according to M signals to be transmitted, wherein M is the number of transmission antennas in a system, and elements in the first row of the orthogonal matrix X are the M signals to be transmitted as x₁, x₂, . . . , x_M, and elements in the other rows are arrangements of the signals to be transmitted and the reverse values of the signals to be transmitted.

4. The method of claim 1, wherein generating the coefficient matrix corresponding to the orthogonal matrix comprises generating the coefficient matrix according to a formula of

$(\begin{array}{cccc}{h}_1^{*}& & & \\ & h_2^{*}& & \\ & & \ddots \end{array}$

h M * ) 



or 



M ∑

m = 1 M 



h m 

2 



( h 1 * h 2 * ⋱

h M * )

wherein M is the number of transmission antennas in a system, and h_m is the channel status information from the number m (m=1, 2, . . . M) transmission antenna in a transmitter to a receiver.

5. The method of claim 1, wherein generating the transmission matrix according to the orthogonal matrix and the coefficient matrix comprises:

weighing each element in the orthogonal matrix according to the coefficient matrix.

6. The method of claim 5, wherein weighing each element in the orthogonal matrix according to the coefficient matrix comprises:

premultiplying the coefficient matrix by the orthogonal matrix.

7. A method for space-time decoding, comprising:

performing a weight-combination for received signals according to channel status information; and

obtaining estimations of transmitted signals corresponding to the received signals by performing detection for the received signals.

8. The method of claim 7, wherein performing the weight-combination for the received signals according to the channel status information comprises:

computing weighted coefficients of the received signals according to the channel status information; and

performing the weight-combination for the received signals according to the weighted coefficients of the received signals.

9. The method of claim 7, further comprising:

estimating the channel status information.

10. An apparatus for space-time coding, comprising:

an orthogonal matrix generating module, for generating an orthogonal matrix for signals to be transmitted;

a coefficient matrix generating module, for generating a coefficient matrix corresponding to the orthogonal matrix according to channel status information; and

a transmission matrix generating module, for generating a transmission matrix according to the orthogonal matrix and the coefficient matrix.

11. The apparatus of claim 10, further comprising:

a signal transmission module, for transmitting signals via a transmission antenna according to the transmission matrix.

12. The apparatus of claim 10, wherein the orthogonal matrix generating module comprises:

a to-be-transmitted signal grouping unit, for dividing the signals into groups according to the number of transmission antennas in a system; and

an orthogonal matrix generating unit, for generating the orthogonal matrix according to the signals grouped, wherein elements in the first row of the orthogonal matrix are the signals to be transmitted, and elements in the other rows are arrangements of the signals to be transmitted and the reverse values of the signals to be transmitted.

13. The apparatus of claim 10, wherein the coefficient matrix generating module comprises:

a channel status information obtaining unit, for obtaining the channel status information; and

a coefficient matrix computing unit, for generating the coefficient matrix according to the channel status information.

14. The apparatus of claim 13, wherein the coefficient matrix computing unit generates the coefficient matrix according to the following formulas:

$<br><br>\left(\begin{array}{cccc}{h}_1^{*}& & & \\ & h_2^{*}& & \\ & & \mathrm{\ddots <br><br>}& \\ & & & h_M^{*}\end{array}\right)<br><br><br><br>\mathrm{or}<br><br><br><br>\frac{\sqrt{M}}{\sqrt{\underset{m=1}{\overset{M}{\sum <br><br>}}<br><br>{<br><br>h_m<br><br>}^2}}<br><br><br><br>\left(\begin{array}{cccc}{h}_1^{*}& & & \\ & h_2^{*}& & \\ & & \mathrm{\ddots <br><br>}& \\ & & & h_M^{*}\end{array}\right)$

wherein M is the number of transmission antennas, and h_m is the channel status information from the number m (m=1, 2, . . . M) antenna in a transmitter to a receiver.

15. An apparatus for space-time decoding, comprising:

a received signals combination module, for performing a weight-combination for received signals according to channel status information; and

a signal detection module, for obtaining estimations of transmitted signals corresponding to the received signals by performing detection for the received signals.

16. The apparatus of claim 15, further comprising:

a channel status information estimating module, for estimating the channel status information.

17. The apparatus of claim 15, further comprising:

a weighted coefficient computing module, for computing weighted coefficients of the received signals according to the channel status information;

wherein

the received signal combination module is further configured for performing the weight-combination for the received signals according to the weighted coefficients.