Multiple-input, multiple-output (MIMO) systems with multiple transmission modes

• US 20030161282A1
• Filed: 02/26/2002
• Published: 08/28/2003
• Est. Priority Date: 02/26/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Medvedev, Irina, Walton, Jay Rod, Wallace, Mark
• Granted Patent: US 6,862,271 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/043 using best eigenmode, e.g. beam forming or beam steering
• CPC Class Codes: H04B 7/0439 utilizing channel inversion
• CPC Class Codes: H04B 7/0443 utilizing "waterfilling" technique
• CPC Class Codes: H04B 7/061 using feedback from receiving side
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0025 Spatial division following the spatial signature of the channel
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Techniques to transmit data on a number of transmission channels in a multi-channel communication system using multiple transmission schemes requiring less channel-state information (CSI). These schemes may include a partial-CSI transmission scheme that transmits a single data stream on each transmit antenna selected for use and a “beam-forming” transmission scheme that allocates all transmit power to a single transmission channel having the best performance. Each transmission scheme may provide good or near-optimum performance for a specific range of operating conditions (or operating SNRs). These multiple transmission schemes may then be combined in a piece-wise fashion to form a “multi-mode” transmission scheme that covers the full range of operating conditions supported by the MIMO system. The specific transmission scheme to be used for data transmission at any given moment would then be dependent on the specific operating condition experienced by the system at that moment.

Claims

1. A method for transmitting data over a plurality of transmission channels in a wireless communication system, comprising:

determining an operating condition of the communication system;

identifying a specific transmission scheme selected from among a plurality of possible transmission schemes based on the determined operating condition;

determining one or more data streams to be transmitted based on the selected transmission scheme; and

processing the one or more data streams based on the selected transmission scheme.

2. The method of claim 1, wherein the specific transmission scheme is selected by evaluating performance of each of the plurality of possible transmission scheme.

3. The method of claim 1, wherein the specific transmission scheme is selected based on an operating signal-to-noise-and-interference ratio (SNR).

4. The method of claim 1, wherein the one or more data streams are further processed based on channel-state information.

5. The method of claim 4, wherein the plurality of transmission schemes includes a partial channel-state information (CSI) transmission scheme.

6. The method of claim 5, wherein the channel-state information for the partial-CSI transmission scheme comprises signal-to-noise-and-interference ratios (SNRs).

7. The method of claim 4, wherein the plurality of transmission schemes include a beam-forming transmission scheme.

8. The method of claim 7, wherein a single transmission channel is selected for use for the beam-forming transmission scheme, and wherein beam-forming is used for a data transmission on the single selected transmission channel.

9. The method of claim 7, wherein the channel-state information for the beam-forming transmission scheme comprises signal-to-noise-and-interference ratio (SNR) and a singular vector for a single selected transmission channel.

10. The method of claim 9, wherein each element of the singular vector is quantized to five bits or less per dimension.

11. The method of claim 4, wherein the plurality of transmission schemes include a beam-steering transmission scheme.

12. The method of claim 11, wherein the channel-state information for the beam-steering transmission scheme comprises signal-to-noise-and-interference ratio (SNR) and a vector of phase values for a plurality of transmit antennas used for data transmission.

13. The method of claim 12, wherein the vector of phase values is based on a singular vector for a principal eigenmode.

14. The method of claim 1, wherein the operating condition is quantified by a signal-to-noise-and-interference ratio (SNR), and wherein a partial-CSI transmission scheme is selected for use if an operating SNR of the communication system is above a threshold SNR, and a beam-forming transmission scheme is selected for use if the operating SNR is below the threshold SNR.

15. The method of claim 1, further comprising:

selecting a rate for each data stream based on a signal-to-noise-and-interference ratio (SNR) achievable for the data stream.

16. The method of claim 1, wherein the wireless communication system is a multiple-input multiple-output (MIMO) communication system and the plurality of transmission channels correspond to a plurality of spatial subchannels of the MIMO communication system.

17. The method of claim 1, wherein the wireless communication system is a wideband multiple-input multiple-output (MIMO) communication system and the plurality of transmission channels correspond to a plurality of spatial subchannels of a plurality of frequency bands.

18. The method of claim 17, wherein one transmission scheme is selected for use for all frequency bands, and wherein one or more data streams are transmitted on each frequency band and are processed based on the selected transmission scheme.

19. The method of claim 17, wherein one transmission scheme is selected for use for each frequency band, and wherein one or more data streams are transmitted on each frequency band and are processed based on the transmission scheme selected for that frequency band.

20. The method of claim 17, wherein a beam-forming transmission scheme is selected for use for each of the plurality of frequency bands.

21. The method of claim 20, wherein total transmit power is allocated such that a common coding and modulation scheme is used for all data streams transmitted on the plurality of frequency bands.

22. The method of claim 17, wherein a partial-CSI transmission scheme is selected for use for each of the plurality of frequency bands.

23. The method of claim 22, wherein total transmit power is allocated such that a common coding and modulation scheme is used for all data streams transmitted on each frequency band.

24. The method of claim 22, wherein total transmit power is allocated such that a common coding and modulation scheme is used for all data streams transmitted on each spatial subchannel.

25. The method of claim 1, wherein the wireless communication system is an orthogonal frequency division multiplexing (OFDM) communication system and the plurality of transmission channels correspond to a plurality of frequency subchannels.

26. A method for transmitting data on a plurality of spatial subchannels in a multiple-input multiple-output (MIMO) communication system, comprising:

determining an operating signal-to-noise-and-interference ratio (SNR) of the MIMO system;

identifying a specific transmission scheme selected from among a plurality of possible transmission schemes based on the operating SNR, wherein each of the plurality of transmission schemes is designated for use for a respective range of operating SNRs;

determining one or more data streams to be transmitted based on the selected transmission scheme; and

processing the one or more data streams based on the selected transmission scheme.

27. The method of claim 26, wherein the plurality of transmission schemes include a partial-CSI transmission scheme and a beam-forming transmission scheme, and wherein the partial-CSI transmission scheme is selected for use if the operating SNR is above a threshold SNR and the beam-forming transmission scheme is selected for use if the operating SNR is below the threshold SNR.

28. A method for transmitting data in a multiple-input multiple-output (MIMO) communication system, comprising:

identifying a specific one of a plurality of transmission channels based on their achieved performance;

determining a vector of phase values corresponding to the selected transmission channel, one phase value for each of a plurality of transmit antennas used for data transmission;

processing data based on a particular coding and modulation scheme; and

transmitting the processed data from each of the plurality of transmit antennas at a particular transmit power and with a phase determined by the phase value associated with the transmit antenna.

29. The method of claim 28, wherein full transmit power is used for each transmit antenna.

30. A memory communicatively coupled to a digital signal processing device (DSPD) capable of interpreting digital information to:

determine an operating condition of a communication system;

select a specific transmission scheme from among a plurality of possible transmission schemes based on the determined operating condition;

determine one or more data streams to be transmitted based on the selected transmission scheme; and

process the one or more data streams based on the selected transmission scheme.

31. A computer program product for facilitating data transmission over a plurality of transmission channels in a wireless communication system, comprising:

code for determining an operating condition of the communication system;

code for selecting a specific transmission scheme from among a plurality of possible transmission schemes based on the determined operating condition;

code for determining one or more data streams to be transmitted based on the selected transmission scheme;

code for directing processing the one or more data streams based on the selected transmission scheme; and

a computer-usable medium for storing the codes.

32. An apparatus in a wireless communication system, comprising:

means for determining an operating condition of the communication system;

means for identifying a specific transmission scheme selected from among a plurality of possible transmission schemes based on the determined operating condition;

means for determining one or more data streams to be transmitted based on the selected transmission scheme; and

means for processing the one or more data streams based on the selected transmission scheme.

33. The apparatus of claim 32, wherein the wireless communication system is a multiple-input multiple-output (MIMO) communication system and the plurality of transmission channels correspond to a plurality of spatial subchannels of the MIMO communication system.

34. The apparatus of claim 32, wherein the specific transmission scheme is selected based on an operating signal-to-noise-and-interference ratio (SNR) of the communication system, and wherein each of the plurality of transmission schemes is designated for use for a respective range of operating SNRs.

35. The apparatus of claim 34, wherein the plurality of transmission schemes include a partial-CSI transmission scheme and a beam-forming transmission scheme, and wherein the partial-CSI transmission scheme is selected for use if the operating SNR is above a threshold SNR and the beam-forming transmission scheme is selected for use if the operating SNR is below the threshold SNR.

36. The apparatus of claim 32, further comprising:

means for selecting a rate for each data stream based on a signal-to-noise-and-interference ratio (SNR) achievable by the data stream.

37. An apparatus in a multiple-input multiple-output (MIMO) communication system, comprising:

means for determining an operating signal-to-noise-and-interference ratio (SNR) of the MIMO system;

means for identifying a specific transmission scheme selected from among a plurality of possible transmission schemes based on the operating SNR, wherein each of the plurality of transmission schemes is designated for use for a respective range of operating SNRs;

means for determining one or more data streams to be transmitted based on the selected transmission scheme; and

means for processing the one or more data streams based on the selected transmission scheme.

38. A controller in a wireless communication system, comprising:

means for receiving an operating condition of the communication system;

means for identifying a specific transmission scheme selected from among a plurality of possible transmission schemes based on the determined operating condition;

means for determining one or more data streams to be transmitted based on the selected transmission scheme; and

means for directing processing of the one or more data streams based on the selected transmission scheme.

39. The controller of claim 38, further comprising:

means for selecting a rate for each data stream based on a signal-to-noise-and-interference ratio (SNR) achievable by the data stream.

40. A base station comprising the controller of claim 38.

41. A transmitter unit in a wireless communication system, comprising:

a controller operative to direct data transmission over a plurality of transmission channels by

receiving an indication of an operating condition of the communication system,

identifying a specific transmission scheme selected from among a plurality of possible transmission schemes based on the operating condition,

determining one or more data streams to be transmitted based on the selected transmission scheme,

selecting a rate for each data stream based in part on an amount of transmit power allocated to the data stream, and

directing processing of the one or more data streams based on the selected transmission scheme;

a transmit (TX) data processor operative to process each data stream based on the selected rate to provide a respective stream of symbols; and

one or more transmitters operative to process one or more symbol streams to provide one or more modulated signals suitable for transmission over a communication channel.

42. The transmitter unit of claim 41, wherein the plurality of transmission schemes include a partial-CSI transmission scheme and a beam-forming transmission scheme.

43. The transmitter unit of claim 42, wherein the controller is operative to select the partial-CSI transmission scheme if an operating signal-to-noise-and-interference ratio (SNR) of the communication system is above a threshold SNR and to select the beam-forming transmission scheme if the operating SNR is below the threshold SNR.

44. The transmitter unit of claim 42, wherein the controller is further operative to utilize peak transmit power for each data stream for the partial-CSI transmission scheme and to allocate all transmit power to a single data stream for the beam-forming transmission scheme.

45. The transmitter unit of claim 42, further comprising:

a TX MIMO processor operative to precondition the stream of symbols for a single data stream based on a singular vector for the beam-forming transmission scheme.

46. A base station comprising the transmitter unit of claim 41.

47. A receiver unit in a wireless communication system, comprising:

a receive (RX) MIMO processor operative to receive and process a plurality of streams of received symbols in accordance with a particular receiver processing scheme to provide at least one stream of recovered symbols, and to derive channel-state information (CSI) for each recovered symbol stream;

a RX data processor operative to process at least one recovered symbol stream in accordance with at least one demodulation and decoding scheme to provide decoded data; and

a TX data processor operative to process the CSI for transmission back to a transmitter unit, and

wherein a specific transmission scheme is selected from among a plurality of possible transmission schemes based on the CSI, wherein one or more data streams are transmitted to the receiver unit based on the selected transmission scheme, and wherein total available transmit power is allocated to the one or more data streams based on the selected transmission scheme.

48. The receiver unit of claim 47, wherein the plurality of transmission schemes include a partial-CSI transmission scheme and a beam-forming transmission scheme, and wherein the partial-CSI transmission scheme is selected if an operating signal-to-noise-and-interference ratio (SNR) is above a threshold SNR and the beam-forming transmission scheme is selected if the operating SNR is below the threshold SNR.

49. The receiver unit of claim 48, wherein for the beam-forming transmission scheme the RX MIMO processor is further operative to pre-condition the plurality of received symbol streams with a singular vector to provide a single recovered symbol stream.

50. The receiver unit of claim 48, wherein for the partial-CSI transmission scheme the RX MIMO processor is further operative to process the plurality of received symbol streams based on a minimum mean square error with successive cancellation (MMSE-SC) receiver processing technique to provide a plurality of recovered symbol streams.

51. A receiver apparatus in a wireless communication system, comprising:

means for processing a plurality of streams of received symbols in accordance with a particular receiver processing scheme to provide at least one stream of recovered symbols, and to derive channel-state information (CSI) for each recovered symbol stream;

means for processing the at least one recovered symbol stream in accordance with at least one demodulation and decoding scheme to provide decoded data; and

means for processing the CSI for transmission back to a transmitter apparatus, and

wherein a specific transmission scheme is selected from among a plurality of possible transmission schemes based on the CSI, wherein one or more transmission data streams are transmitted to the receiver apparatus based on the selected transmission scheme, and wherein total available transmit power is allocated to the one or more data streams based on the selected transmission scheme.