Multiple modulation schemes in single rate layering wireless communication systems

• US 8,457,152 B2
• Filed: 06/16/2005
• Issued: 06/04/2013
• Est. Priority Date: 07/16/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gorokhov, Alexei, Agrawal, Avneesh, Gore, Dhananjay, Kadous, Tamer
• Primary Examiner(s): Rinehart, Mark
• Assistant Examiner(s): BROCKMAN, ANGEL T
• Application Number:
  US11/155,204
• Publication Number:
  US 20060014499A1
• Time in Patent Office: 2,910 Days
• Field of Search: 370/465, 370/204
• US Class Current: 370/465
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/005 Iterative decoding, including iteration between signal detection and decoding operation
• CPC Class Codes: H04L 1/06 using space diversity

Abstract

A MIMO communication system is adapted to encode multiple data streams at the same adaptable rate. Accordingly, the set of all possible modulation/rate combinations to all modulations with common rates is decreased thus resulting in the reduction of the number of possible packet formats carrying the data streams. Rate prediction is made more error-resilient, in part, due to the averaging over all information rates. Furthermore, the signaling overhead of the packets is reduced. Therefore, the tradeoff between the desired transmission rate granularity on the one hand, and robustness/signaling overhead on the other hand, is controlled by adjusting the coding rate.

Claims

1. A wireless communication device comprising:

a plurality of encoders each configured to receive and encode a different one of a plurality of data segments to generate an encoded data segment;

wherein each of the plurality of encoders is configured to encode the respective data segment that the encoder receives at a same rate for simultaneously encoded data segments;

a plurality of modulators each configured to receive and modulate a different one of the plurality of encoded data segments to generate a modulated data segment according to a modulation technique, wherein at least two of the plurality of modulators utilize different modulation techniques for simultaneously modulated data segments; and

a plurality of transmitters each configured to receive and process a different one of the modulated data segments and to deliver the processed data segment to a different one of a plurality of associated transmit antennas for transmission,

wherein a first subset of the plurality of data segments that are received and encoded is associated with a first data stream and a second subset of the plurality of data segments that are received and encoded is associated with a second data stream, the first data stream being different from the second data stream, and

wherein for streams delivered to subchannels of the wireless communication device, the modulators are configured to select appropriate modulation sizes to accommodate information rates I₁ . . . I_m, corresponding to signal-to-noise ratios of the subchannels, wherein m is the number of the plurality of encoders, the plurality of data segments or the plurality of modulators, respectively, and for the information rates I₁ . . . I_m and an actual number of bits per symbol n₁ . . . n_m, the encoders are configured to use a single coding rate R, where R =R₁ =. . . =Rm and is defined as follows;

2. The wireless communication device of claim 1, further comprising a beamforming block coupled between the plurality of modulators and the plurality of transmitters.

3. The wireless communication device of claim 1, wherein each of the plurality modulators is configured to modulate the data segment it receives using a different modulation technique for simultaneously modulated data segments.

4. The wireless communication device of claim 1, wherein each of the plurality of transmitters is configured to convert the modulated data segment it receives from a baseband signal to an RF signal.

5. A method comprising:

encoding each of a plurality of data segments at a same rate to generate a plurality of encoded data segments;

modulating each of the plurality of encoded data segments to generate a plurality of modulated data segments, wherein at least two of the plurality of encoded data segments are modulated according to different modulation techniques; and

transmitting the plurality of processed signals via a plurality of associated transmit antennas

receiving and processing the plurality of modulated data segments, and transmitting the plurality of processed data segments via a plurality of associated transmit antennas,

wherein a first subset of the plurality of data segments that are received and encoded is associated with a first data stream and a second subset of the plurality of data segments that are received and encoded is associated with a second data stream, the first data stream being different from the second data stream, and

wherein for streams delivered to subchannels of a transmitting end, appropriate modulation sizes are selected to accommodate information rates I₁ . . . I_m corresponding to signal-to-noise ratios of the subchannels, wherein m is the number of the plurality of data segments, the plurality of encoded data segments or the plurality of modulated data segments, respectively, and for the information rates I₁ . . . I_m and an actual number of bits per symbol n₁ . . . n_m, a single coding rate R is utilized, where R =R₁ =. . . =Rm and is defined as follows;

6. The method of claim 5 further comprising eigenbeamforming the modulated data segments prior to transmitting.

7. The method of claim 5 wherein modulating comprises modulating each of the plurality of encoded data segments according to different modulation techniques.

8. The method of claim 5 wherein processing each of the plurality of modulated data segments comprises converting each of the modulated data segments from a baseband signal to an RF signal.

9. A transmitter comprising:

means for receiving and encoding each of a plurality of data segments at a same rate to generate a plurality of encoded data segments;

means for modulating at least two of the plurality of encoded data segments using different modulation techniques to generate a plurality of modulated data segments; and

means for receiving and processing the plurality of modulated data segments, and transmitting the processed data segments via a plurality of associated transmit antennas,

wherein a first subset of the plurality of data segments that are received and encoded is associated with a first data stream and a second subset of the plurality of data segments that are received and encoded is associated with a second data stream, the first data stream being different from the second data stream, and

wherein for streams delivered to subchannels of the transmitter, the means for modulating are configured to select appropriate modulation sizes to accommodate information rates I₁ . . . I_m corresponding to signal-to-noise ratios of the subchannels, wherein m is the number of the plurality of data segments, the plurality of encoded data segments or the plurality of modulated data segments, respectively, and for the information rates I₁ . . . I_m and an actual number of bits per symbol n₁ . . . n_m, the means for receiving and encoding are configured to use a single coding rate R, where R =R₁ =. . . =Rm and is defined as follows;

10. The transmitter of claim 9 further comprising:

means for modulating each of the plurality of encoded data using a different modulation technique.

11. The transmitter of claim 9 further comprising:

means for converting each of the modulated data segments from a baseband signal to an RF signal.

12. A non-transitory computer-readable medium having stored thereon processor-executable software instructions configured to cause a processor to perform steps comprising:

encoding each of a plurality of data segments at a same rate to generate a plurality of encoded data segments;

modulating each of the plurality of encoded data segments to generate a plurality of modulated data segments, wherein at least two of the plurality encoded data segments are modulated according to different modulation techniques; and

receiving and processing the plurality of modulated data segments, and transmitting the plurality of processed data segments via a plurality of associated transmit antennas,

wherein a first subset of the plurality of data segments that are received and encoded is associated with a first data stream and a second subset of the plurality of data segments that are received and encoded is associated with a second data stream, the first data stream being different from the second data stream, and

wherein for streams delivered to subchannels of a transmitting end, appropriate modulation sizes are selected to accommodate information rates I₁ . . . I_m corresponding to signal-to-noise ratios of the subchannels, wherein m is the number of the plurality of data segments, the plurality of encoded data segments or the plurality of modulated data segments, respectively, and for the information rates I₁ . . . I_m and an actual number of bits per symbol n₁ . . . n_m, a single coding rate R is utilized, where R =R₁ =. . . =Rm and is defined as follows;

13. The non-transitory computer-readable medium of claim 12, wherein the stored processor-executable software instructions are configured to cause a processor to perform further steps comprising:

eigenbeamforming the modulated data segments prior to transmitting.

14. The non-transitory computer-readable medium of claim 12, wherein the stored processor-executable software instructions are configured to cause a processor to perform further steps comprising:

modulating each of the plurality of encoded data segments according to different modulation techniques.

15. The non-transitory computer-readable medium of claim 12, wherein the stored processor-executable software instructions are configured to cause a processor to perform further steps comprising:

converting each of the transformed signals from a baseband signal to an RF signal.

16. The non-transitory computer-readable medium of claim 12, wherein the stored processor-executable software instructions are configured to cause a processor to perform further steps comprising:

filtering each of the transformed signals,

amplifying each of the transformed signals; and

converting each of the transformed signals from a digital signal to an analog signal.

17. A wireless communication device comprising:

a plurality of encoders each configured to receive and encode a different one of a plurality of data segments to generate an encoded data segment;

wherein each of the plurality of encoders is configured to encode the respective data segment that the encoder receives at a single rate for simultaneously encoded data segments; and

a plurality of modulators each configured to receive and modulate a different one of the plurality of encoded data segments to generate a modulated data segment according to a modulation technique, wherein at least two of the plurality of modulators utilize different modulation techniques for simultaneously modulated data segments;

wherein a first subset of the plurality of data segments that are received and encoded is associated with a first data stream and a second subset of the plurality of data segments that are received and encoded is associated with a second data stream, the first data stream being different from the second data stream, and

wherein the encoders are configured to use a single coding rate that is less than or equal to a ratio of (1) a sum of information rates of the subchannels and (2) a sum of bits per symbol for the subchannels.