Method and apparatus for space-time coding and decoding

• US 7,675,845 B2
• Filed: 10/25/2007
• Issued: 03/09/2010
• 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
• Primary Examiner(s): Pham; Chi H.
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US11/924,307
• Publication Number:
  US 20090116375A1
• Time in Patent Office: 866 Days
• Field of Search: 455/59
• 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 in a wireless system comprising M transmission antennas, the method comprising:

a transmitter of the wireless system generating an orthogonal matrix for signals to be transmitted by the transmitter;

the transmitter of the wireless system generating a coefficient matrix corresponding to the orthogonal matrix according to at least one of the formulas;

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

wherein h_m includes channel status information from the m^th transmission antenna to a receiver; and

the transmitter of the wireless system 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 M of transmission antennas in the 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 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 transmission matrix according to the orthogonal matrix and the coefficient matrix comprises:

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

5. The method of claim 4, wherein weighing each element in the orthogonal matrix according to the coefficient matrix comprises:

premultiplying the coefficient matrix by the orthogonal matrix.

6. An apparatus for space-time coding in a wireless system having M transmission antennas, the apparatus 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 at least one of the formulas;

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

wherein h_m includes channel status information from the m^th transmission antenna to a receiver; and

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

7. The apparatus of claim 6, further comprising:

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

8. The apparatus of claim 6, wherein the orthogonal matrix generating module comprises:

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

9. The apparatus of claim 6, 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.