DATA TRANSMISSION WITH SPATIAL SPREADING IN A MIMO COMMUNICATION SYSTEM

• US 20110142097A1
• Filed: 06/15/2010
• Published: 06/16/2011
• Est. Priority Date: 01/13/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Walton, Jay Rodney, Howard, Steven J., Ketchum, John W., Wallace, Mark S.
• Granted Patent: US 8,325,844 B2
• Time in Patent Office: Days
• US Class Current: 375/141
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0678 using different spreading codes between antennas code allocation H04J13/16
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• 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 25/0224 using sounding signals
• CPC Class Codes: H04L 5/0023 Time-frequency-space

Abstract

For data transmission with spatial spreading, a transmitting entity (1) encodes and modulates each data packet to obtain a corresponding data symbol block, (2) multiplexes data symbol blocks onto NS data symbol streams for transmission on NS transmission channels of a MIMO channel, (3) spatially spreads the NS data symbol streams with steering matrices, and (4) spatially processes NS spread symbol streams for full-CSI transmission on NS eigenmodes or partial-CSI transmission on NS spatial channels of the MIMO channel. A receiving entity (1) obtains NR received symbol streams via NR receive antennas, (2) performs receiver spatial processing for full-CSI or partial-CSI transmission to obtain NS detected symbol streams, (3) spatially despreads the NS detected symbol streams with the same steering matrices used by the transmitting entity to obtain NS recovered symbol streams, and (4) demodulates and decodes each recovered symbol block to obtain a corresponding decoded data packet.

Claims

1. A computer-program storage apparatus for transmitting data from a transmitting entity to a receiving entity in a wireless multiple-input multiple-output (MIMO) communication system comprising a memory having one or more software modules stored thereon, the one or more software modules being executable by one or more processors and the one or more software modules comprising:

code for processing data to obtain a plurality of streams of data symbols for transmission on a plurality of transmission channels in a MIMO channel between the transmitting entity and the receiving entity;

code for performing spatial spreading on the plurality of streams of data symbols with at least two different steering matrices for a plurality of subbands to obtain a plurality of streams of spread symbols, wherein the spatial spreading with the plurality of steering matrices randomizes the plurality of transmission channels for the plurality of streams of data symbols; and

code for performing spatial processing on the plurality of streams of spread symbols to obtain a plurality of streams of transmit symbols for transmission from a plurality of transmit antennas at the transmitting entity.

2. The apparatus of claim 1, wherein the code for performing spatial processing comprise:

code for multiplying the plurality of streams of spread symbols with matrices of eigenvectors to transmit the plurality of streams of spread symbols on a plurality of eigenmodes of the MIMO channel.

3. The apparatus of claim 1, wherein the code for performing spatial processing comprise:

code for providing each of the plurality of streams of spread symbols as one of the plurality of streams of transmit symbols.

4. The apparatus of claim 1, wherein the code for processing data comprise:

code for encoding and modulating data for each of the plurality of streams of data symbols based on a rate selected for the stream of data symbols.

5. The apparatus of claim 4, further comprising:

code for obtaining the rate for each stream of data symbols, the rate being selected based on a signal-to-noise-and-interference ratio (SNR) of a transmission channel for the stream of data symbols.

6. The apparatus of claim 1, wherein the code for processing data comprise:

code for encoding and modulating each of a plurality of packets of data to obtain a block of data symbols, and

code for multiplexing a plurality of blocks of data symbols generated for the plurality of packets of data onto the plurality of streams of data symbols.

7. The apparatus of claim 6, wherein the code for encoding and modulating comprise:

code for encoding each packet of data based on a Turbo code, a convolutional code, or a low density parity check (LDPC) code to obtain a block of coded data, and

code for symbol mapping each block of coded data based on a modulation scheme to obtain a block of data symbols.

8. The apparatus of claim 6, wherein the code for multiplexing the plurality of blocks of data symbols comprise:

code for multiplexing each block of data symbols onto one of the plurality of streams of data symbols.

9. The apparatus of claim 6, wherein the code for multiplexing the plurality of blocks of data symbols comprise:

code for multiplexing each block of data symbols onto all of the plurality of streams of data symbols.

10. The apparatus of claim 1, wherein the code for performing spatial spreading comprise:

code for performing spatial processing on the plurality of streams of data symbols using a set of L steering matrices, where L is an integer greater than one.

11. The apparatus of claim 10, further comprising:

code for generating the L steering matrices as unitary matrices having orthogonal columns.

12. The apparatus of claim 10, further comprising:

code for selecting a steering matrix from among the L steering matrices for each time interval, and wherein the spatial spreading is performed for each time interval with the steering matrix selected for the time interval.

13. The apparatus of claim 10, further comprising:

code for selecting a steering matrix from among the L steering matrices for each group of at least one frequency subband, and wherein the spatial spreading is performed for each group of at least one frequency subband with the steering matrix selected for the group.

14. The apparatus of claim 1, further comprising:

code for processing each of the plurality of streams of transmit symbols for orthogonal frequency division multiplexing (OFDM).