Space-time coded OFDM system for MMDS applications

• US 8,374,272 B2
• Filed: 01/29/2008
• Issued: 02/12/2013
• Est. Priority Date: 11/06/2000
• Status: Active Grant

• Current Assignee: DIRECTV, LLC (AT&T, Inc.)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: Hammons, A. Roger Jr., El-Gamal, Hesham, Lee, Lin-Nan, Kay, Stan, MacDonald, Andrew, Rozmaryn, Jack, Beidas, Bassel
• Primary Examiner(s): HEARD, ERIN FILE
• Application Number:
  US12/011,658
• Publication Number:
  US 20080130772A1
• Time in Patent Office: 1,841 Days
• Field of Search: 375/267
• US Class Current: 375/267
• 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 of encoding, comprising:

receiving an input signal; and

generating an encoded signal, based on the input signal, using space-frequency coding, wherein the space-frequency coding includes use of a transfer function matrix that is one of a set of binary full-rank matrices, and wherein a structure of each matrix of the set of binary full-rank matrices is defined based at least in part on a number of paths in an intersymbol interference (ISI) channel and a number of antennas.

2. The method according to claim 1, wherein the encoded signal is modulated according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme.

3. The method according to claim 2, wherein the modulated signal is transmitted using multiple transceivers.

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

5. The method according to claim 3, wherein the encoded signal is transmitted according to an error control scheme that includes automatic repeat request (ARQ).

6. The method according to claim 1, wherein the antennas include at least one of a set of two transmit antennas and two receive antennas, a set of four transmit antennas and four receive antennas, or a set of four transmit antennas and two receive antennas.

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

trellis-based code.

8. An apparatus comprising:

an encoder configured to receive an input signal, and to generate an encoded signal, based on the input signal, using space-frequency coding, wherein the space-frequency coding includes use of a transfer function matrix that is one of a set of binary full-rank matrices, and wherein a structure of each matrix of the set of binary full-rank matrices is defined based at least in part on a number of paths in an intersymbol interference (ISI) channel and a number of antennas.

9. The apparatus according to claim 8, wherein the encoded signal is modulated according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme.

10. The apparatus according to claim 9, the modulated signal is transmitted using multiple transceivers.

11. The apparatus according to claim 10, wherein the encoder adaptively encodes based on quantity of the transceivers.

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

13. The apparatus according to claim 8, wherein the antennas include at least one of a set of two transmit antennas and two receive antennas, a set of four transmit antennas and four receive antennas, or a set of four transmit antennas and two receive antennas.

14. The apparatus according to claim 8, wherein the encoder encodes based on a rate ½

trellis-based code.