Hierarchical modulation for communication channels in single-carrier frequency division multiple access

• US 8,259,848 B2
• Filed: 06/09/2008
• Issued: 09/04/2012
• Est. Priority Date: 06/08/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Malladi, Durga Prasad
• Primary Examiner(s): Liu, Shuwang
• Assistant Examiner(s): Singh, Hirdepal
• Application Number:
  US12/135,793
• Publication Number:
  US 20090042511A1
• Time in Patent Office: 1,548 Days
• Field of Search: 375/260, 375/261, 375/267, 375/269, 375/271, 375/295, 375/297, 375/298, 375/299, 375/302, 375/316, 375/322, 375/340, 375/346
• US Class Current: 375/298
• CPC Class Codes: H04L 27/183 Multiresolution systems
• CPC Class Codes: H04L 27/2604 Multiresolution systems by means of multiresolution subcarriers H04L27/183, H04L27/3488
• CPC Class Codes: H04L 27/3488 Multiresolution systems
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601

Abstract

System(s) and method(s) are provided to transmit simultaneously a first and a second communication channel in a single-carrier waveform format with disparate error rate requirements. First channel and second channel are coded individually to form an alphabet for a first and second constellation. Prior to transmission, bits of information of the first and second channels are modulated with a hierarchical modulation constellation is generated through a combination of a first a second constellation; each constellation is assigned a configurable weight (e.g., a “hierarchic weight”) that is expressed in terms of a configurable energy ratio. The energy ratio determines the resilience of bits associated with the first and second channel. Bit mapping within the first and second constellation provides redundancy to mitigate error rate within each quadrant of the hierarchical constellation. Hierarchical modulation of more than two channel can be accomplished through the same principal of individual coding and constellation composition.

Claims

1. A method employed in a wireless communication system, the method comprising:

encoding P bits (P a positive integer) of information of a first communication channel in a first modulation constellation;

encoding Q bits (Q a positive integer) of information of a second communication channel in a second modulation constellation;

combining the encoded first modulation constellation and the encoded second modulation constellation to generate a hierarchical modulation constellation, wherein combining includes configuring a set of weights and assigning a first weight in the configured set of weights to the first encoded constellation and a second weight in the configured set of weights to the second encoded constellation, wherein the first weight (α

) and the second weight (β

) are configurable through a configurable control parameter (ε

); and

modulating the first communication channel and the second communication channel in a common set of tones with the hierarchical modulation constellation.

2. The method of claim 1, the configurable control parameter determines an erasure rate of at least one of the encoded P bits of information of the first communication channel or the encoded Q bits of information of the second communication channel.

3. The method of claim 2, wherein configuring a set of weights further comprises optimizing the configurable control parameter to determine a relative erasure rate among the first communication channel and the second communication channel that optimizes at least one of a quality of service.

4. The method of claim 3, wherein the first weight, the second weight, and the control parameter satisfy the condition

5. The method of claim 4, wherein one of the first weight or the second weight equals

6. The method of claim 1, wherein the first communication channel is one of an ACK (acknowledge) channel, or an NACK (not-acknowledge) channel, and the second communication channel is a CQI (channel quality indication) channel.

7. The method of claim 1, wherein the first communication channel is one of an RI (rank indication) channel or a PMI (precoding matrix indicator channel), and the second communication channel is a CQI (channel quality indication) channel.

8. The method of claim 1, further comprising conveying the hierarchically modulated first communication channel and second communication channel.

9. The method of claim 1, further comprising storing the set of configured weights.

10. The method of claim 1, wherein each of the first modulation constellation or the second modulation constellation is at least one of a binary phase-shift keying modulation (BPSK), a quadrature phase-shift keying (QPSK) modulation, a quadrature amplitude modulation (QAM), M-ary QAM (M-QAM), with M a positive integer.

11. A wireless communication device comprising:

a processor configured;

to encode P bits (P a positive integer) of information of a first communication channel in a first modulation constellation;

to encode Q bits (Q a positive integer) of information of a second communication channel in a second modulation constellation;

to assign a first weight (α

) to the first encoded constellation and a second weight (β

) to the second encoded constellation to generate a hierarchical modulation constellation through the combination of the weighted first encoded constellation and the weighted second encoded constellation, wherein the first weight (α

) and the second weight (β

) are configurable through a configurable control parameter (ε

); and

to modulate the first communication channel and the second communication channel in a common set of tones with the hierarchical modulation constellation; and

a memory coupled to the processor.

12. The wireless communication device of claim 11, the configurable control parameter determines an erasure rate of at least one of the encoded P bit of information of the first communication channel or the encoded Q bits of information of the second communication channel.

13. The wireless communication device of claim 12, further comprising conveying the hierarchically modulated first communication channel and second communication channel.

14. The wireless communication device of claim 13, wherein the first communication channel is one of an RI (rank indication) channel or a PMI (precoding matrix indicator channel), and the second communication channel is a CQI (channel quality indication) channel.

15. The wireless communication device of claim 13, wherein each of the first modulation constellation or the second modulation constellation is at least one of a binary phase-shift keying modulation (BPSK), a quadrature phase-shift keying (QPSK) modulation, a quadrature amplitude modulation (QAM), M-ary QAM (M-QAM), with M a positive integer.

16. The wireless communication device of claim 12, wherein the memory retains the first weight and the second weight.

17. The wireless communication device of claim 16, wherein the memory further stores at least one of a set of first constellations, a set of second constellations, and a set of hierarchical constellations.

18. The wireless communication device of claim 11, wherein the first weight, the second weight, and the control parameter satisfy the condition

19. The wireless communication device of claim 18, wherein one of the first weight or the second weight equals

20. An apparatus that operates in a wireless communication environment, the apparatus comprising:

means for encoding a first set of bits of information of a first communication channel in a first modulation constellation;

means for encoding a second set of bits of information of a second communication channel in a second modulation constellation;

means for assigning a first weight (α

) to the first encoded constellation and a second weight (β

) to the second encoded constellation to generate a hierarchical modulation constellation through the combination of the weighted first encoded constellation and the weighted second encoded constellation, wherein the first weight (α

) and the second weight (β

) are configurable through a configurable control parameter (ε

);

means for modulating the first communication channel and the second communication channel in a common set of tones with the hierarchical modulation constellation; and

means for conveying the hierarchically modulated first communication channel and second communication channel.

21. The apparatus of claim 20, wherein the first weight (α

), the second weight (β

), and the control parameter (ε

) satisfy the condition

22. The apparatus of claim 21, wherein the configurable control parameter determines an erasure rate of at least one of the encoded first set of bits of information of the first communication channel or the encoded second set of bits of information of the second communication channel.

23. The apparatus of claim 22, wherein the first set comprises 2 bits and the second set comprises 2 bits.

24. A computer program product comprising a non-transitory computer-readable medium including:

code for causing at least one computer to encode P bits (P a positive integer) of a first communication channel in a first layer of a modulation constellation symbol;

code for causing at least one computer to encode Q bits (Q a positive integer) of a second communication channel in a second layer of a modulation constellation symbol;

code for causing at least one computer to generate a hierarchical modulation constellation symbol through a weighted combination of the encoded first layer of a modulation constellation symbol and the encoded second layer of a modulation constellation, wherein the code for causing at least one computer to generate the hierarchical modulation constellation comprises code for causing the at least one computer to configure a set of weights, and code for causing the at least one computer to assign a first weight in the configured set of weights to the encoded first layer of a modulation constellation symbol and a second weight in the configured set of weights to the encoded second layer of a modulation constellation symbol, wherein the first weight (α

) and the second weight (β

) are configurable through a configurable control parameter (ε

); and

code for causing at least one computer to modulate the first communication channel and the second communication channel in a common set of tones with a set of hierarchical modulation constellation symbols.

25. The computer program product of claim 24, the configurable control parameter determines an erasure rate of at least one of the encoded P bit of information of the first communication channel or the encoded Q bits of information of the second communication channel.

26. The computer program product of claim 25, wherein the first weight, the second weight, and the control parameter satisfy the condition

27. The computer program product of claim 26, wherein one of the first weight or the second weight equals

28. The computer program product of claim 27, wherein the first communication channel is one of an ACK (acknowledge) channel, or a NACK (not-acknowledge) channel, and the second communication channel is a CQI (channel quality indication) channel.

29. The computer program product of claim 27, wherein the first communication channel is one of an RI (rank indication) channel or a PMI (precoding matrix indicator channel), and the second communication channel is a CQI (channel quality indication) channel.