METHOD AND SYSTEM FOR PROVIDING MULTI-INPUT-MULTI-OUTPUT (MIMO) DOWNLINK TRANSMISSION

• US 20090168916A1
• Filed: 01/30/2009
• Published: 07/02/2009
• Est. Priority Date: 05/19/2004
• Status: Active Grant

• Current Assignee: DIRECTV, LLC (AT&T, Inc.)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: Song, Jian, Karimullah, Khalid
• Granted Patent: US 8,243,706 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04B 7/0862 receiver computing weights based on information from the transmitter
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0028 Variable division signaling therefor H04L5/0092
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading

Abstract

An approach is provided for supporting transmission in a multi-input-multi-output (MIMO) communication system including a plurality of terminals. A preamble portion of a frame is transmitted by a multiple transmit antennas of a hub using Orthogonal Frequency Division Multiplexing (OFDM) to the terminals over a channel, wherein each of the terminals determines a characteristic of the channel with respect to the transmit antennas as feedback information. The hub receives the feedback information from the terminals. The hub selects, according to the feedback information, a subset of the antennas for transmission of a remaining portion of the frame to the terminal.

Claims

1. A method for supporting transmission of data in a multi-input-multi-output (MIMO) communication system to one or more terminals, the method comprising:

assigning a first plurality of sets of Orthogonal Frequency Division Multiplexing (OFDM) sub-carriers to a corresponding plurality of antennas, the sets comprising distinct sub-sets of the sub-carriers;

transmitting a preamble portion of a frame from the antennas to the one or more terminals over a downlink channel, the downlink channel comprising at least the OFDM sub-carriers;

receiving, from at least one of the terminals, a frequency response of the downlink channel with respect to the antennas as feedback information;

assigning, for one or more terminals from which feedback information was received, a second set of the OFDM sub-carriers to a subset of the antennas based on the feedback information; and

transmitting a data portion of the frame from the assigned subset of the antennas to one or more of the terminals.

2. A method as defined in claim 1, wherein one or more of the first plurality of sets of OFDM sub-carriers comprise consecutive OFDM sub-carriers over an entire allocated bandwidth.

3. A method as defined in claim 1, further comprising assigning a second plurality of sets of the OFDM sub-carriers to the plurality of antennas, the second plurality of sets comprising distinct sub-sets of the sub-carriers that are different than the sub-sets of the first plurality of sets of OFDM sub-carriers.

4. A method as defined in claim 3, wherein the feedback information is based on the first plurality of sets of OFDM sub-carriers and the second plurality of sets of OFDM sub-carriers.

5. A method as defined in claim 1, further comprising setting one or more transmission parameters based on the feedback information.

6. A method as defined in claim 5, wherein the transmission parameters comprise one or more of adaptive modulation, phase compensation, Singular Value Decomposition, or beam forming.

7. A method as defined in claim 1, wherein the feedback information is determined based on a Fourier Transform of the preamble portion.

8. A hub device for supporting transmission of data in a multi-input-multi-output (MIMO) communication system to one or more terminals, comprising:

a processor; and

a memory, storing instructions therein configured to cause the processor to;

assign a first plurality of sets of Orthogonal Frequency Division Multiplexing (OFDM) sub-carriers to a corresponding plurality of antennas, the sets comprising distinct sub-sets of the sub-carriers;

transmit a preamble portion of a frame from the antennas to the one or more terminals over a downlink channel, the downlink channel comprising at least the OFDM sub-carriers;

receive, from at least one of the terminals, a frequency response of the downlink channel with respect to the antennas as feedback information;

assign, for one or more terminals from which feedback information was received, a second set of the OFDM sub-carriers to a subset of the antennas based on the feedback information; and

transmit a data portion of the frame from the assigned subset of the antennas to one or more of the terminals.

9. A hub device as defined in claim 8, wherein one or more of the first plurality of sets of OFDM sub-carriers comprise consecutive OFDM sub-carriers over an entire allocated bandwidth.

10. A hub device as defined in claim 8, wherein the instructions further cause the processor to assign a second plurality of sets of the OFDM sub-carriers to the plurality of antennas, the second plurality of sets comprising distinct sub-sets of the sub-carriers that are different than the sub-sets of the first plurality of sets of OFDM sub-carriers.

11. A hub device as defined in claim 10, wherein the feedback information is based on the first plurality of sets of OFDM sub-carriers and the second plurality of sets of OFDM sub-carriers.

12. A hub device as defined in claim 8, wherein the instructions further cause the processor to set one or more transmission parameters based on the feedback information.

13. A hub device as defined in claim 12, wherein the transmission parameters comprise one or more of adaptive modulation, phase compensation, Singular Value Decomposition, or beam forming.

14. A hub device as defined in claim 8, wherein the feedback information is determined based on a Fourier Transform of the preamble portion.

15. A computer readable medium storing machine accessible instructions thereon, configured to cause a processor to support transmission in a multi-input-multi-output (MIMO) communication system to one or more terminals, and cause the processor to:

assign a first plurality of sets of Orthogonal Frequency Division Multiplexing (OFDM) sub-carriers to a corresponding plurality of antennas, the sets comprising distinct sub-sets of the sub-carriers;

transmit a preamble portion of a frame from the antennas to the one or more terminals over a downlink channel, the downlink channel comprising at least the OFDM sub-carriers;

receive, from at least one of the terminals, a frequency response of the downlink channel with respect to the antennas as feedback information;

assign, for one or more terminals from which feedback information was received, a second set of the OFDM sub-carriers to a subset of the antennas based on the feedback information; and

transmit a data portion of the frame from the assigned subset of the antennas to one or more of the terminals.

16. A hub device as defined in claim 15, wherein one or more of the first plurality of sets of OFDM sub-carriers comprise consecutive sub-carriers over an entire allocated bandwidth.

17. A hub device as defined in claim 15, wherein the instructions further cause the processor to assign a second plurality of sets of the OFDM sub-carriers to the plurality of antennas, the second plurality of sets comprising distinct sub-sets of the sub-carriers that are different than the sub-sets of the first plurality of sets of OFDM sub-carriers.

18. A hub device as defined in claim 17, wherein the feedback information is based on the first plurality of sets of OFDM sub-carriers and the second plurality of sets of OFDM sub-carriers.

19. A hub device as defined in claim 15, wherein the instructions further cause the processor to set one or more transmission parameters based on the feedback information.

20. A hub device as defined in claim 15, wherein the feedback information is determined based on a Fourier Transform of the preamble portion.

21. A method for supporting transmission of data in a multi-input-multi-output (MIMO) communication system to one or more terminals, the method comprising:

assigning a first plurality of sets of Orthogonal Frequency Division Multiplexing (OFDM) sub-carriers to a corresponding plurality of antennas, the sets comprising distinct sub-sets of the sub-carriers;

transmitting a preamble portion of a frame from the antennas to the one or more terminals over a downlink channel, the downlink channel comprising at least the OFDM sub-carriers;

receiving, from at least one of the terminals, a frequency response of the downlink channel with respect to the antennas as feedback information;

assigning, for one or more terminals from which feedback information was received, a second one or more sets of the OFDM sub-carriers to a subset of the antennas based on the feedback information, wherein a number of the second sets of OFDM sub-carriers corresponds to a number of the terminals from which feedback information was received; and

transmitting a data portion of the frame from the assigned subset of the antennas to the terminals from which feedback information was received via the respective second sets of OFDM sub-carriers.