MIMO SYSTEM WITH MULTIPLE SPATIAL MULTIPLEXING MODES

• US 20080267098A1
• Filed: 05/05/2008
• Published: 10/30/2008
• Est. Priority Date: 10/25/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Howard, Steven J., Ketchum, John W., Walton, J. Rodney, Wallace, Mark S.
• Granted Patent: US 8,355,313 B2
• Time in Patent Office: Days
• US Class Current: 370/280
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0421 utilizing implicit feedback, e.g. steered pilot signals
• CPC Class Codes: H04B 7/043 using best eigenmode, e.g. beam forming or beam steering
• CPC Class Codes: H04B 7/0434 using multiple eigenmodes
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0628 Diversity capabilities
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• 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: H04B 7/0871 using different reception schemes, at least one of them being a diversity reception scheme
• CPC Class Codes: H04J 11/003 at the transmitter transmission to multiple receive units in multiple input multiple output [MIMO] H04B7/0452; transmit antenna weighting H04B7/0615
• CPC Class Codes: H04J 11/0053 using co-ordinated multipoint transmission/reception co-ordinated antenna or beam-forming aspects H04B7/022
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• 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 1/0017 where the mode-switching is based on Quality of Service requirement
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/0242 : using matrix methods
• CPC Class Codes: H04L 25/0248 : Eigen-space methods
• CPC Class Codes: H04L 25/03343 : Arrangements at the transmitter end
• CPC Class Codes: H04L 25/03891 : Spatial equalizers MIMO diversity systems H04B7/0413
• CPC Class Codes: H04L 27/2601 : Multicarrier modulation systems
• CPC Class Codes: H04L 27/261 : Details of reference signals
• CPC Class Codes: H04L 27/2647 : Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/2675 : Pilot or known symbols
• CPC Class Codes: H04L 5/0073 : Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 16/28 : using beam steering
• CPC Class Codes: H04W 52/50 : at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 72/046 : the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 74/04 : Scheduled access hybrid access H04W74/02

Abstract

A MIMO system supports multiple spatial multiplexing modes for improved performance and greater flexibility. These modes may include (1) a single-user steered mode that transmits multiple data streams on orthogonal spatial channels to a single receiver, (2) a single-user non-steered mode that transmits multiple data streams from multiple antennas to a single receiver without spatial processing at a transmitter, (3) a multi-user steered mode that transmits multiple data streams simultaneously to multiple receivers with spatial processing at a transmitter, and (4) a multi-user non-steered mode that transmits multiple data streams from multiple antennas (co-located or non co-located) without spatial processing at the transmitter(s) to receiver(s) having multiple antennas. For each set of user terminal(s) selected for data transmission on the downlink and/or uplink, a spatial multiplexing mode is selected for the user terminal set from among the multiple spatial multiplexing modes supported by the system.

Claims

1. A method of transmitting data in a wireless multiple-access multiple-input multiple-output (MIMO) communication system, comprising:

selecting at least one user terminal for data transmission;

selecting a spatial multiplexing mode, from among a plurality of spatial multiplexing modes supported by the system, to use for the at least one user terminal;

selecting a plurality of rates for a plurality of data streams to be transmitted via a plurality of spatial channels of a MIMO channel for the at least one user terminal; and

scheduling the at least one user terminal for data transmission with the plurality of selected rates and the selected spatial multiplexing mode.

different spatial multiplexing modes

2. The method of claim 1, wherein one user terminal is selected for data transmission and the selected spatial multiplexing mode is a steered spatial multiplexing mode.

3. The method of claim 2, further comprising:

spatially processing the plurality of data streams with a plurality of steering vectors to transmit the plurality of data streams on orthogonal spatial channels to the one user terminal.

4. The method of claim 1, wherein one user terminal is selected for data transmission and the selected spatial multiplexing mode is a non-steered spatial multiplexing mode.

5. The method of claim 4, further comprising:

providing the plurality of data streams for transmission from a plurality of antennas to the one user terminal.

6. The method of claim 1, wherein a plurality of user terminals are selected for data transmission and the selected spatial multiplexing mode is a steered spatial multiplexing mode.

7. The method of claim 6, further comprising:

spatially processing the plurality of data streams with a plurality of steering vectors to steer the plurality of data streams to the plurality of user terminals.

8. The method of claim 6, further comprising:

performing receiver spatial processing on a plurality of received symbol streams to obtain estimates of the plurality of data streams transmitted by the plurality of user terminals, wherein each data stream is processed with a respective steering vector to steer the data stream.

9. The method of claim 1, wherein a plurality of user terminals are selected for data transmission and the selected spatial multiplexing mode is a non-steered spatial multiplexing mode.

10. The method of claim 9, further comprising:

performing receiver spatial processing on a plurality of received symbol streams to obtain estimates of the plurality of data streams transmitted by the plurality of user terminals.

11. The method of claim 9, further comprising:

providing the plurality of data streams for transmission from a plurality of antennas to the plurality of user terminals each having multiple antennas.

12. The method of claim 1, wherein the MIMO system is a time division duplex (TDD) system.

13. The method of claim 12, wherein the selected spatial multiplexing mode is a steered spatial multiplexing mode if the at least one user terminal is calibrated and downlink channel response is reciprocal of uplink channel response.

14. The method of claim 12, wherein the selected spatial multiplexing mode is a non-steered spatial multiplexing mode if the at least one user terminal is uncalibrated and downlink channel response is not reciprocal of uplink channel response.

15. The method of claim 1, wherein the selecting a plurality of rates includes estimating signal-to-noise-and-interference ratios (SNRs) of the plurality of spatial channels, and

selecting the plurality of rates based on the estimated SNRs of the plurality of spatial channels.

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

a terminal selector operative to select at least one user terminal for data transmission;

a mode selector operative to select a spatial multiplexing mode, from among a plurality of spatial multiplexing modes supported by the system, to use for the at least one user terminal;

a rate selector operative to select a plurality of rates for a plurality of data streams to be transmitted via a plurality of spatial channels of a MIMO channel for the at least one user terminal; and

a scheduler operative to schedule the at least one user terminal for data transmission with the plurality of selected rates and the selected spatial multiplexing mode.

17. The apparatus of claim 16, further comprising:

a transmit spatial processor operative to spatially process the plurality of data streams in accordance with the selected spatial multiplexing mode to obtain a plurality of transmit symbol streams for transmission from a plurality of antennas to the at least one user terminal.

18. The apparatus of claim 16, further comprising:

a receive spatial processor operative to spatially process a plurality of received symbol streams in accordance with the selected spatial multiplexing mode to obtain estimates of the plurality of data streams transmitted by the at least one user terminal.

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

means for selecting at least one user terminal for data transmission;

means for selecting a spatial multiplexing mode, from among a plurality of spatial multiplexing modes supported by the system, to use for the at least one user terminal;

means for selecting a plurality of rates for a plurality of data streams to be transmitted via a plurality of spatial channels of a MIMO channel for the at least one user terminal; and

means for scheduling the at least one user terminal for data transmission with the plurality of selected rates and the selected spatial multiplexing mode.

20. The apparatus of claim 19, further comprising:

means for spatially processing the plurality of data streams in accordance with the selected spatial multiplexing mode to obtain a plurality of transmit symbol streams for transmission from a plurality of antennas to the at least one user terminal.

21. The apparatus of claim 19, further comprising:

means for spatially processing a plurality of received symbol streams in accordance with the selected spatial multiplexing mode to obtain estimates of the plurality of data streams transmitted by the at least one user terminal.