Methods and apparatus for transmitting layered and non-layered data via layered modulation

• US 7,630,451 B2
• Filed: 01/11/2006
• Issued: 12/08/2009
• Est. Priority Date: 01/11/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Vijayan, Rajiv, Collins, Bruce, Chung, Seong Taek, Chari, Murali Ramaswamy, Gautam, Shusheel, Krishnamurthi, Rajeev
• Primary Examiner(s): Torres; Juan A
• Application Number:
  US11/330,796
• Publication Number:
  US 20060183287A1
• Time in Patent Office: 1,427 Days
• Field of Search: 375/261, 375/298, 370/20, 455/60
• US Class Current: 375/261
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0058 Block-coded modulation
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 2001/0098 Unequal error protection
• CPC Class Codes: H04L 27/3488 Multiresolution systems
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601

Abstract

A media access control (MAC) layer controller can manage base layer data and enhancement layer data in a layered modulation system. The MAC layer controller can process both base layer data and enhancement layer data and map the encoded symbols to a layered modulation constellation when both are present. If data for one of the layers terminates, then the MAC layer controller can generate and supply predetermined stuffing data to the layer lacking additional data. The MAC layer controller can send a control signal to the physical layer hardware to cause the hardware to map the layered signals having the stuffing data to a modified signal constellation. The MAC controller can also generate an overhead message that indicates the occurrence of the stuffing data. The receiver can receive the overhead message and can use the information to configure the receiver for the layered modulation constellation or the modified signal constellation.

Claims

1. A method of transmitting data, the method comprising:

receiving base layer data;

encoding the base layer data to base layer symbols;

receiving enhancement layer data;

determining termination of the enhancement layer data prior to termination of the base layer data;

generating stuffing data;

appending the stuffing data to the enhancement layer data;

encoding the enhancement layer data appended with the stuffing data to enhancement layer symbols;

mapping base layer symbols in combination with enhancement layer symbols corresponding to the enhancement layer data to a first constellation; and

mapping base layer symbols in combination with enhancement layer symbols corresponding to the stuffing data to a second constellation.

2. The method of claim 1, wherein the first constellation comprises 16 constellation points.

3. The method of claim 1, wherein the second constellation comprises a QPSK constellation.

4. The method of claim 1, wherein the second constellation comprises a subset of constellation points from the first constellation.

5. The method of claim 1, wherein mapping the base layer symbols in combination with the enhancement layer symbols to the second constellation comprises mapping the base layer symbols to the second constellation without regard to the enhancement layer symbols.

6. The method of claim 1, wherein the stuffing data comprises a predetermined sequence.

7. The method of claim 1, wherein the stuffing data comprises a pseudorandom sequence.

8. A method of transmitting data, the method comprising:

generating a layered signal;

mapping at least a portion of the layered signal to a point of a layered modulation constellation;

transmitting the point of the layered modulation constellation over a logical channel having a plurality of time slots during a first time slot of the logical channel;

generating a non-layered signal;

mapping at least a portion of the non-layered signal to a point of a non-layered modulation constellation; and

transmitting the point of the non-layered modulation constellation over the logical channel during a second time slot of the logical channel.

9. The method of claim 8, further comprising assigning the logical channel to a subset of OFDM subcarriers.

10. The method of claim 8, wherein the layered signal comprises at least one base layer symbol and at least one enhancement layer symbol.

11. The method of claim 8, wherein the non-layered signal comprises at least one base layer symbol and at least one enhancement layer symbol, the at least one enhancement layer symbol generated by encoding predetermined stuffing data.

12. The method of claim 8, wherein the non-layered modulation constellation comprises a QPSK constellation.

13. The method of claim 8, wherein the non-layered modulation constellation comprises a subset of constellation points from the layered modulation constellation.

14. A transmitter configured to transmit data, the transmitter comprising:

a base layer processing block configured to receive base layer data and encode the base layer data to base layer symbols;

an enhancement layer processing block configured to receive enhancement layer data and encode the enhancement layer data to enhancement layer symbols;

a controller configured to determine a termination of the enhancement layer data, generate stuffing data in response to the termination of the enhancement layer data, and couple the stuffing data to the enhancement layer processing block; and

a signal mapper coupled to the base layer processing block and the enhancement layer processing block, and configured to select a constellation from a plurality of constellations based in part on the presence of stuffing data and to map a combination of at least one base layer symbol with at least one enhancement layer symbols to a point of the selected constellation.

15. The transmitter of claim 14, wherein the signal mapper selects a non-layered constellation when stuffing data is present, and wherein the signal mapper maps the base layer symbol to the non-layered constellation without regard to the enhancement layer symbols.

16. The transmitter of claim 14, wherein the controller comprises a stuffing data generator configured to generate stuffing data comprising a predetermined sequence.

17. The transmitter of claim 14, wherein the controller comprises a stuffing data generator configured to generate stuffing data comprising a pseudorandom sequence.

18. The transmitter of claim 14, wherein the controller comprises an overhead message generator configured to generate an overhead message indicating the presence of stuffing data.

19. The transmitter of claim 14, further comprising a channel assignment module configured to modulate a tone with the constellation point.

20. A transmitter configured to transmit data, the transmitter comprising:

a base layer processing block configured to receive base layer data and encode the base layer data to base layer symbols;

an enhancement layer processing block configured to receive enhancement layer data and encode the enhancement layer data to enhancement layer symbols;

a controller configured to generate a control signal based on a presence of enhancement layer data; and

a signal mapper coupled to the base layer processing block and the enhancement layer processing block, and configured to map a combination of at least one base layer symbols and at least one enhancement layer symbols to a constellation selected from a plurality of constellations based on the control signal.

21. A transmitter configured to transmit data, the transmitter comprising:

means for encoding base layer data to base layer symbols;

means for determining an active base only mode;

means for generating stuffing data in response to the active base only mode;

means for appending the stuffing data to enhancement layer data;

means for encoding the enhancement layer data appended with the stuffing data to enhancement layer symbols;

means for mapping base layer symbols in combination with enhancement layer symbols corresponding to the enhancement layer data to a first constellation; and

means for mapping base layer symbols in combination with enhancement layer symbols corresponding to the stuffing data to a second constellation.

22. A computer readable medium having computer executable instructions stored thereon which, when executed, cause components of a wireless transmitter to perform a method comprising:

receiving base layer data;

encoding the base layer data to base layer symbols;

receiving enhancement layer data;

determining termination of the enhancement layer data prior to termination of the base layer data;

generating stuffing data;

appending the stuffing data to the enhancement layer data;

encoding the enhancement layer data appended with the stuffing data to enhancement layer symbols;

mapping base layer symbols in combination with enhancement layer symbols corresponding to the enhancement layer data to a first constellation; and

mapping base layer symbols in combination with enhancement layer symbols corresponding to the stuffing data to a second constellation.

23. A computer readable medium having computer executable instructions stored thereon which, when executed, cause components of a wireless transmitter to perform a method comprising:

generating a layered signal;

mapping at least a portion of the layered signal to a point of a layered modulation constellation;

transmitting the point of the layered modulation constellation over a logical channel having a plurality of time slots during a first time slot of the logical channel;

generating a non-layered signal;

mapping at least a portion of the non-layered signal to a non-layered modulation constellation; and

transmitting the point of the non-layered modulation constellation over the logical channel during a second time slot of the logical channel.