Space-time block coding systems and methods

• US 9,356,735 B2
• Filed: 09/13/2012
• Issued: 05/31/2016
• Est. Priority Date: 04/01/2004
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Tong, Wen, Jia, Ming, Zhu, Peiying, Chloma, Alexandre Mikhailovich, Bakouline, Mikhail Germanovich, Kreindeline, Vitali Borisovich
• Primary Examiner(s): Wong, Linda
• Application Number:
  US13/615,341
• Publication Number:
  US 20130003795A1
• Time in Patent Office: 1,356 Days
• Field of Search: 375219-220, 375/259, 375/261, 375/265, 375/278, 375/284, 375/298, 375/309, 375/343, 375/350, 37524026-24029, 375229-236, 375/295, 375/296, 375299-301, 375/316, 375324-326, 375340-341, 375/346, 375/347, 375/221, 37524026-24027, 375/285, 375/302, 375/320, 375/322, 375/348, 375/349, 375/354, 455132-141
• US Class Current: 1/1
• CPC Class Codes: H04L 1/0618 Space-time coding

Abstract

Although orthonormal space-time coding matrices provide for optimal communication system performance in that associated correlation matrices include no non-zero off-diagonal elements, unity code rate orthonormal coding matrices are difficult to identify for arbitrary communication network equipment. According to embodiments of the present invention, non-orthonormal space-time coding matrices, for which associated correlation matrices include non-zero off-diagonal elements, are used to encode data symbols. The non-orthonormal space-time coding matrices are more easily determined, and undesirable effects of the non-zero off-diagonal components are reduced by selecting a coding matrix from among a number of such matrices. For example, a particular space-time coding matrix may be selected from a number of generated space-time coding matrices based on a number of non-zero off-diagonal elements or a power of a trace of the associated correlation matrices.

Claims

1. A transmitter in a wireless communication system comprising:

a processor configured to determine a plurality of space-time coding matrices, the plurality of space-time coding matrices each having an associated correlation matrix comprising a plurality of non-zero off-diagonal elements and to select one of the plurality of space-time coding matrices for which the associated correlation matrix has a least number of non-zero off-diagonal elements; and

an encoder to encode data symbols using the selected space-time coding matrix; and

to apply a phase rotation factor to the encoded data symbols prior to transmission.

2. The transmitter of claim 1, wherein the encoder determines the phase rotation factor to be applied to encoded data bits to reduce values of the non-zero off-diagonal elements of the correlation matrix associated with the selected space-time coding matrix.

3. The transmitter of claim 1, wherein the selected space-time coding matrix is punctured, and the data symbols are encoded using the punctured selected space-time coding matrix.

4. The transmitter of claim 1, wherein the phase rotation factor is determined based on feedback information received from a receiver to which the encoded data symbols are to be transmitted.

5. The transmitter of claim 4, wherein the feedback information comprises a code representing a phase angle of the phase rotation factor, determined based on communication channel gain factors.

6. The transmitter of claim 5, wherein the code has a length selected from the group consisting of:

1 bit, 2 bits, and 4 bits.

7. The transmitter of claim 5, wherein the processor implements a phasor for converting the code to the phase rotation factor.

8. The transmitter of claim 1, further comprising:

a plurality of multipliers for applying a scrambling code to respective ones of the encoded data symbols; and

a plurality of delay stages connected to at least one of the plurality of multipliers for delaying at least one of the encoded symbols and the scrambling code for the at least one of the plurality of multipliers.

9. The transmitter of claim 1, wherein each of the plurality of space-time coding matrices has a form

10. A wireless communication system comprising:

a receiver comprising;

a plurality of antennas, wherein the plurality of antennas receive data symbols encoded using a space-time coding matrix selected from a plurality of space-time coding matrices, the plurality of space-time coding matrices each having a respective associated correlation matrix comprising a plurality of non-zero off-diagonal elements, wherein the respective associated correlation matrix for the selected space-time coding matrix has a least number of non-zero off-diagonal elements;

a decoder to decode the received data symbols and to determine feedback information; and

a transmitting device transmitting the feedback information, to a transmitter, from which the plurality of antennas receive the data symbols, wherein the feedback information comprises a phase angle for a phase rotation factor to be applied by the transmitter to transmit the encoded data symbols.

11. The receiver of claim 10, wherein the feedback information is determined based on communication channel gain factors.

12. The receiver of claim 10, wherein the phase rotation factor is used to reduce values of off-diagonal elements of a correlation matrix associated with a space time coding matrix used to encode subsequent transmitted data.

13. The receiver of claim 12, wherein the space-time coding matrix has a form

14. A method in a transmitter comprising:

determining a plurality of space-time coding matrices, the plurality of space-time coding matrices each having an associated correlation matrix comprising a plurality of non-zero off-diagonal elements;

encoding data symbols using a space-time coding matrix selected from the plurality of space-time coding matrices with the associated correlation matrix having a least number of non-zero off-diagonal elements; and

applying a phase rotation factor to the encoded data symbols, the phase rotation factor being determined to reduce values of off-diagonal elements of the correlation matrix.

15. The method of claim 14, wherein determining the phase rotation factor comprises receiving the phase rotation factor from a receiver to which the data symbols are to be transmitted, and calculating the phase rotation factor based on the feedback information.

16. The method of claim 15, wherein the feedback information comprises a code representing a phase angle for the phase rotation factor determined on the basis of communication channel gain factors.

17. The method of claim 14, wherein each of the plurality of space-time coding matrices has a form

18. The method of claim 14, further comprising applying a scrambling code to respective ones of the encoded data symbols and delaying the scrambling code and the encoded data symbols.