Space-time coded OFDM system for MMDS applications

• US 7,342,875 B2
• Filed: 11/05/2001
• Issued: 03/11/2008
• Est. Priority Date: 11/06/2000
• Status: Expired due to Fees

• Current Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: MacDonald, Andrew, Lee, Lin-Nan, Hammons, A. Roger Jr., Kay, Stan, Beidas, Bassel, El-Gamal, Hesham, Rozmaryn, Jack
• Primary Examiner(s): Orgad; Edan
• Assistant Examiner(s): Lee; Andrew C.
• Application Number:
  US10/012,066
• Publication Number:
  US 20020165626A1
• Time in Patent Office: 2,318 Days
• Field of Search: 370/203, 370/208, 370/210, 370/343, 375/219, 375/267, 375/285, 375/296, 375/299, 375/347, 375/348, 455/101, 455/504, 455/506, 455/561, 455/562.1
• US Class Current: 370/219
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04L 27/2602 Signal structure

Abstract

A communications system includes a base station that is configured to transmit a signal that is modulated according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme, wherein the signal is encoded using space-frequency coding. The base station includes a plurality of multiple-input multiple-output (MIMO) transceivers. The system includes a terminal that is configured to receive the modulated signal. The above arrangement is particularly applicable to providing multichannel multipoint distribution services (MMDS) over a radio communications system.

Claims

1. A method for communicating over a radio communications system, the method comprising:

encoding a signal using space-frequency coding by utilizing a transfer function matrix that is an element of a set of binary full-rank matrices whose structure is defined by number of paths in an intersymbol Interference (ISI) channel and number of transmit antennas;

modulating the encoded signal according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme; and

transmitting the modulated signal to a terminal using a plurality of multiple-input multiple-output (MIMO) transceivers.

2. The method according to claim 1, wherein the predetermined modulation scheme includes at least of one Quadrature Amplitude Modulation (QAM) and Quadrature Phase Shift Keying (QPSK).

3. The method according to claim 1, wherein the encoding step is adaptive based on quantity of the plurality of MIMO transceivers.

4. The method according to claim 1, wherein the transmitting step is performed according to an error control scheme that includes automatic repeat request (ARQ).

5. The method according to claim 1, wherein the plurality of transceivers in the transmitting step are coupled to a plurality of antennas that are as at least one of a set of two transmit antennas and two receive antennas, a set of four transmit antennas and four receive antennas, and a set of four transmit antennas and two receive antennas.

6. The method according to claim 1, wherein the encoding step is based on a rate ½

trellis-based code.

7. A device for communicating over a radio communications system, the device comprising:

an encoder configured to encode a signal using space-frequency coding by utilizing a transfer function matrix that is an element of a set of binary full-rank matrices whose structure is defined by number of paths in an intersymbol interference (ISI) channel and number of transmit antennas;

a modulator configured to modulate the encoded signal according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme; and

a plurality of multiple-input multiple-output (MIMO) transceivers coupled to the modulator, each of the transceivers being configured to transmit the modulated signal to a terminal.

8. The device according to claim 7, wherein the predetermined modulation scheme includes at least of one Quadrature Amplitude Modulation (QAM) and Quadrature Phase Shift Keying (QPSK).

9. The device according to claim 7, wherein the encoder adaptively encodes based on quantity of the plurality of MIMO transceivers.

10. The device according to claim 7, wherein the signal is transmitted according to an error control scheme that includes automatic repeat request (ARQ).

11. The device according to claim 7, further comprising:

a plurality of antennas coupled to the plurality of transceivers the plurality of antennas comprising at least one of a set of two transmit antennas and two receive antennas, a set of four transmit antennas and four receive antennas, and a set of four transmit antennas and two receive antennas.

12. The device according to claim 7, wherein the encoder encodes based on a rate ½

trellis-based code.

13. A communications system comprising:

a base station transmitting a signal that is modulated according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme, wherein the signal is encoded using space-frequency coding associated with a transfer function matrix that is an element of a set of binary full-rank matrices whose structure is defined by number of paths in an intersymbol interference (ISI) channel and number of transmit antennas, the base station including a plurality of multiple-input multiple-output (MIMO) transceivers; and

a terminal receiving the modulated signal.

14. The system according to claim 13, wherein the predetermined modulation scheme includes at least of one Quadrature Amplitude Modulation (QAM) and Quadrature Phase Shift Keying (QPSK).

15. The system according to claim 13, wherein the base station adaptively encodes based an quantity of the plurality of MIMO transceivers.

16. The system according to claim 13, wherein the signal is transmitted according to an error control scheme that includes automatic repeat request (ARQ).

17. The system according to claim 13, wherein the base station includes at least one of a set of two transmit antennas and two receive antennas, a set of four transmit antennas and four receive antennas, and a set of four transmit antennas and two receive antennas, the terminal including two transmit antennas and two receive antennas.

18. The system according to claim 13, wherein the base station encodes based on a rate ½

trellis-based code.

19. An apparatus for communicating over a radio communications system, the apparatus comprising:

means for encoding a signal using space-frequency coding by utilizing a transfer function matrix that is an element of a set of binary full-rank matrices whose structure is defined by number of paths in an intersymbol interference (ISI) channel and number of transmit antennas;

means for modulating the encoded signal according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme; and

means for transmitting the modulated signal to a terminal using a plurality of multiple-input multiple-output (MIMO) transceivers.

20. The apparatus according to claim 19, wherein the predetermined modulation scheme includes at least of one Quadrature Amplitude Modulation (QAM) and Quadrature Phase Shift Keying (QPSK).

21. The apparatus according to claim 19, wherein the encoding means adaptively encodes based on quantity of the plurality of MIMO transceivers.

22. The apparatus according to claim 19, wherein the signal is transmitted according to an error control scheme that includes automatic repeat request (ARQ).

23. The apparatus according to claim 19, wherein the plurality of transceivers are coupled to a plurality of antennas the plurality of antennas comprising at least one of a set of two transmit antennas and two receive antennas, a set of four transmit antennas and four receive antennas, and a set of four transmit antennas and two receive antennas.

24. The apparatus according to claim 19, wherein the encoding means encodes based on a rate ½

trellis-based code.

25. A computer-readable storage medium for storing one or more sequences of one or more instructions for communicating over a radio communications system, the one or more sequences of one or more instructions including instructions which, when executed by one or more processors, cause the one or more processors to perform the step of:

encoding a signal using space-frequency coding by utilizing a transfer function matrix that is an element of a set of binary full-rank matrices whose structure is defined by number of paths in an intersymbol interference (ISI) channel and number of transmit antennas, the encoded signal being modulated according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme, wherein the modulated signal is transmitted a terminal using a plurality of multiple-input multiple-output (MIMO) transceivers.

26. The computer-readable storage medium according to claim 25, wherein the predetermined modulation scheme includes at least of one Quadrature Amplitude Modulation (QAM) and Quadrature Phase Shift Keying (QPSK).

27. The computer-readable storage medium according to claim 25, wherein the encoding step is adaptive based on quantity of the plurality of MIMO transceivers.

28. The computer-readable storage medium according to claim 25, wherein the signal is transmitted according to an error control scheme that includes automatic repeat request (ARQ).

29. The computer-readable storage medium according to claim 25, wherein the plurality of transceivers are coupled to a plurality of antennas that are as at least one of a set of two transmit antennas and two receive antennas, a set of four transmit antennas and four receive antennas, and a set of four transmit antennas and two receive antennas.

30. The computer-readable storage medium according to claim 25, wherein the encoding step is based on a rate ½

trellis-based code.

31. A method of communicating in a multichannel multipoint distribution service (MMDS) system that includes a plurality of transmit antennas, the method comprising:

receiving an encoded signal representing space-time codes; and

transforming an intersymbol interference (ISI) channel that is characteristic of a channel supporting transmission of the encoded signal into a flat black fading channel,

wherein the space-time codes are generated based on a set of binary full-rank matrices whose structure is defined by number of paths in the ISI channel and number of transmit antennas, the space-time codes exploiting diversity associated with the flat block fading channel.