Method and system for optional closed loop mechanism with adaptive modulations for multiple input multiple output (MIMO) wireless local area network (WLAN) system

• US 7,924,943 B2
• Filed: 04/20/2005
• Issued: 04/12/2011
• Est. Priority Date: 02/07/2005
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Hansen, Christopher J., Kim, Joonsuk, Aldana, Carlos H.
• Primary Examiner(s): Payne; David C
• Assistant Examiner(s): Perez; James M
• Application Number:
  US11/110,241
• Publication Number:
  US 20060176972A1
• Time in Patent Office: 2,183 Days
• Field of Search: 375/133, 375/130, 375/132, 375/299, 375/295, 375219-221, 375/296, 375/316, 375/377, 700/1, 700/28, 700/53, 343/757, 455/7, 455/25, 434/757
• US Class Current: 375/299
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication

Abstract

Aspects of a method and system for an optional closed loop mechanism with adaptive modulations for a multiple input multiple output (MIMO) WLAN system are provided. One aspect of the system may comprise a receiver that may select, for a plurality of spatial streams, a modulation type and/or coding rate. The receiver may communicate a message, via an RF channel, that comprises a plurality of modulation types and/or coding rates. The receiver may configure for receiving subsequent data based on at least one selected modulation type and/or coding rate. Another aspect of the system may comprise a transmitter that may receive a message, via an RF channel, that comprises a specification of, for a plurality of spatial streams, a plurality of modulation types and/or coding rates. The system may configure for transmitting subsequent data based on at least one of the received modulation types and/or coding rates.

Claims

1. A method for communicating information, the method comprising:

performing by one or more processors and/or circuits in a multiple input multiple output (MIMO) communications system;

receiving signals via a plurality of spatial streams;

computing a corresponding geometric mean signal to noise ratio (SNR) value for each of said plurality of spatial streams based on said received signals;

selecting a corresponding plurality of modulation type identifiers and/or one or more coding rate identifiers based on said plurality of computed corresponding geometric mean signal to noise ratio values;

communicating a physical layer protocol data unit (PPDU), via one or more uplink radio frequency (RF) channels, said communicated physical layer protocol data unit comprising one or more fields comprising said selected corresponding plurality of modulation type identifiers; and

receiving one or more subsequent physical layer protocol data units, wherein a header portion of said received one or more subsequent physical layer protocol data units comprises a plurality of modulation type identifier values, wherein at least a portion of said plurality of modulation type identifier values is based on at least a portion of one or both of said selected corresponding plurality of modulation type identifiers and/or said selected one or more coding rate identifiers.

2. The method according to claim 1, comprising receiving said received one or more subsequent physical layer protocol data units via one or more downlink RF channels.

3. The method according to claim 1, comprising generating said received one or more subsequent physical layer protocol data units based on subsequent signals received via said plurality of spatial streams.

4. The method according to claim 3, comprising generating said received one or more subsequent physical layer protocol data units by decoding said received subsequent signals based on at least a portion of said plurality of modulation type identifier values.

5. The method according to claim 1, wherein said header portion of said received one or more subsequent physical layer protocol data units comprise a closed loop indicator field.

6. The method according to claim 1, comprising determining an adaptive modulation indication for receiving said received one or more subsequent physical layer protocol data units based on a comparison of said plurality of modulation type identifier values.

7. The method according to claim 5, comprising determining a beamforming indication for receiving said received one or more subsequent physical layer protocol data units based on a value for said closed loop indicator field.

8. A method for communicating information, the method comprising:

performing by one or more processors and/or circuits in a MIMO communications system;

generating a physical layer protocol data unit (PPDU);

configuring a value for a closed loop indicator field, wherein a header portion of said generated physical layer protocol data unit comprises said closed loop indicator field; and

transmitting said generated physical layer protocol data unit via a plurality of spatial streams, utilizing beamforming, based on said configured value for said closed loop indicator field.

9. The method according to claim 8, wherein said header portion comprises a plurality of modulation type identifier fields.

10. The method according to claim 9, comprising configuring a corresponding value for each of said plurality of modulation type identifier fields, wherein said plurality of modulation type identifier fields correspond to said plurality of spatial streams.

11. The method according to claim 10, comprising encoding at least a portion of said generated physical layer protocol data unit for said transmitting via a corresponding one of said plurality of spatial streams based on said corresponding value for said corresponding one of said plurality of spatial streams.

12. The method according to claim 10, wherein each said configured corresponding value is equal based on said configured value for said closed loop indicator field.

13. The method according to claim 8, comprising transmitting a beamforming indication for receiving said transmitted physical layer protocol data unit based on said configured value for said closed loop indicator field.

14. The method according to claim 8, comprising determining said configured value for said closed loop indicator field based on one or more received physical layer protocol data units.

15. A system for communicating information in a multiple input multiple output (MIMO) communications system, the system comprising:

a receiver, in a multiple input multiple output (MIMO) communications system, that is operable to receive signals via a plurality of spatial streams;

said receiver is operable to compute a corresponding geometric mean signal to noise ratio (SNR) value for each of said plurality of spatial streams based on said received signals;

said receiver is operable to select a corresponding plurality of modulation type identifiers and/or one or more coding rate identifiers based on said plurality of computed corresponding geometric mean signal to noise ratio values;

said receiver is operable to communicate a physical layer protocol data unit (PPDU), via one or more uplink radio frequency (RF) channels, said communicated physical layer protocol data unit comprising one or more fields comprising said selected corresponding plurality of modulation type identifiers; and

said receiver is operable to receive one or more subsequent physical layer protocol data units, wherein a header portion of said received one or more subsequent physical layer protocol data units comprises a plurality of modulation type identifier values, wherein at least a portion of said plurality of modulation type identifier values is based on at least a portion of one or both of said selected corresponding plurality of modulation type identifiers and/or said selected one or more coding rate identifiers.

16. The system according to claim 15, wherein said receiver is operable to receive said received one or more subsequent physical layer protocol data units via one or more downlink RF channels.

17. The system according to claim 15, wherein said receiver is operable to generate said received one or more subsequent physical layer protocol data units based on subsequent signals received via said plurality of spatial streams.

18. The system according to claim 17, wherein said receiver is operable to generate said received one or more subsequent physical layer protocol data units by decoding said received subsequent signals based on at least a portion of said plurality of modulation type identifier values.

19. The system according to claim 15, wherein said receiver is operable to determine an adaptive modulation indication for receiving said received one or more subsequent physical layer protocol data units based on a comparison of said plurality of modulation type identifier values.

20. The system according to claim 15, wherein said header portion of said received one or more subsequent physical layer protocol data units comprise a closed loop indicator field.

21. The system according to claim 20, wherein said receiver is operable to determine a beamforming indication for receiving said received one or more subsequent physical layer protocol data units based on a value for said closed looped indicator field.

22. A system for communicating information, the system comprising:

a transmitter, for use in a MIMO communications system, said transmitter is operable to generate a physical layer protocol data unit (PPDU);

said transmitter is operable to configure a value for a closed loop indicator field, wherein a header portion of said generated physical layer protocol data unit comprises said closed loop indicator field; and

said transmitter is operable to transmit said generated physical layer protocol data unit via a plurality of spatial streams, utilizing beamforming, based on said configured value for said closed loop indicator field.

23. The system according to claim 22, wherein said header portion comprises a plurality of modulation type identifier fields.

24. The system according to claim 23, wherein said transmitter is operable to configure a corresponding value for each of said plurality of modulation type identifier fields, wherein said plurality of modulation type identifier fields correspond to said plurality of spatial streams.

25. The system according to claim 24, wherein said transmitter is operable to encode at least a portion of said generated physical layer protocol data unit for said transmitting via a corresponding one of said plurality of spatial streams based on said corresponding value for said corresponding one of said plurality of spatial streams.

26. The system according to claim 24, wherein each said configured corresponding value is equal based on said configured value for said closed loop indicator field.

27. The system according to claim 22, wherein said transmitter is operable to transmit a beamforming indication for receiving said transmitted physical layer protocol data unit based on said configured value for said closed loop indicator field.

28. The system according to claim 22, wherein said transmitter is operable to determine said configured value for said closed loop indicator field based on one or more received physical layer protocol data units.