Method and apparatus for constellation shaping

• US 20040008794A1
• Filed: 07/10/2002
• Published: 01/15/2004
• Est. Priority Date: 07/10/2002
• Status: Active Grant

• Current Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Original Assignee: SolarFlare Communications Incorporated (Advanced Micro Devices, Inc.)
• Inventors: McClellan, Brett Anthony
• Granted Patent: US 7,065,167 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 1/006 Trellis-coded modulation
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 25/4917 using multilevel codes

Abstract

A method and apparatus is disclosed for facilitating high-speed data communication. In one embodiment a receiver is configured to include error correction coding in an interleaved environment to increase data transmission rates. In one embodiment the signal mapping scheme includes constellation shaping to reduce transmit power levels. In one embodiment 8-state Ungerboeck trellis coding is implemented with 4-dimensional PAM 10 signal mapping.

Claims

1. A method for mapping data and control codes to symbol values comprising:

receiving a signal;

analyzing the signal to determine if the signal comprises a control code or data;

responsive to the analyzing, translating data to a data symbol value, wherein the data symbol values are selected from a group of symbol values reserved for data; and

responsive to the analyzing, translating control codes to a control code symbol value, wherein the control code symbol values are selected from a group of symbol values reserved for control codes;

wherein the average value of the group of symbol values reserved for data is zero.

2. The method of claim 1, wherein receiving a signal comprises receiving one or more signals transmitted over two or more channels.

3. The method of claim 1, wherein the group of symbol values reserved for data comprises 8192 symbol values.

4. The method of claim 1, wherein the signal comprises binary information.

5. The method of claim 1, wherein analyzing comprises comparing the signal to a group of signal values reserved for control codes.

6. A method for creating a constellation of available symbol values for mapping data into symbols comprising:

determining a total number of data values to be mapped into the constellation;

defining a set of symbol values from the constellation reserved for data, wherein the average value of the set of symbol values reserved for data comprises zero; and

defining an association between data and a symbol value.

7. The method of claim 6, further comprising defining a set of symbol values reserved for control codes from the constellation.

8. The method of claim 6, wherein the constellation comprises 1000 data points.

9. The method of claim 6, wherein each symbol value may comprise one of ten different levels.

10. The method of claim 6, wherein the constellation comprises a four dimensional constellation.

11. A system for mapping data and a control codes into symbol values comprising:

an input configured to receive data and control codes;

control logic configured to translate data and control codes to symbol values;

wherein the control logic is configured to map a control code to a symbol value reserved for control codes and map data to a symbol value reserved for data and wherein the symbol values reserved for data have an average level of zero.

12. The system of claim 11, wherein the symbol values reserved for data comprise 8192 symbol values.

13. The system of claim 11, wherein as a result of the symbol values being reserved for data having an average level of zero, the average level during transmission of data is zero.

14. The system of claim 11, wherein the symbol values comprises ten level pulse amplitude modulated symbols.

15. A system for mapping data and a control codes into symbol values comprising:

an input configured to receive a signal;

a processor connected to the input and configured to;

analyze the signal to identify data and control codes;

translate the data into symbol values reserved for data; and

translate the control codes into symbol values reserved for control codes;

wherein the symbol values reserved for data have an average power level of zero.

16. The system of claim 15, further comprising memory accessible by the processor and configured to store symbol values.

17. The system of claim 15, wherein the symbol values reserved for data comprise 8192 symbol values.

18. The system of claim 15, wherein translating the data into a symbol value comprises translating two or more bits of binary data into a symbol value selected from a group of symbol values reserved for data and having an average level of zero.

19. The system of claim 15, wherein the symbol values comprise ten level pulse amplitude modulated symbols.

20. The system of claim 15, wherein the symbol values are selected from the set of symbol values consisting of −

9, −

7, −

5, −

3, −

1, 1, 3, 5, 7, and 9, and the processor is further configured to group the symbol values reserved for data into four dimensional symbol sets that do not include two or more symbol values selected from the group consisting of −

9 and +9.

21. A method for processing symbol values comprising:

receiving a symbol value;

analyzing the symbol value;

responsive to the analyzing, converting the symbol value to either two or more bits of data associated with the symbol or a control code associated with the symbol;

wherein the symbol values associated with the two or more bits of data have an average value of zero.

22. The method of claim 21, wherein analyzing comprises comparing the symbol value to a plurality of symbol values stored in a memory to thereby map the symbol value to either two or more bits of data or a control code.

23. The method of claim 21, wherein the receiving comprises receiving a symbol value during each clock cycle on each of four channels.

24. The method of claim 21, wherein the symbol value comprises a symbol representing a 10PAM symbol.

25. A system for mapping data and a control codes into symbol values comprising:

means for receiving a signal comprised of data and control codes;

means for analyzing the signal to determine if the signal comprises a control code or data;

means for translating the data into a symbol values reserved for data;

means for translating the control codes into a symbol values reserved for control codes; and

means for outputting one or more symbol values, wherein the symbol values reserved for data comprise symbol values having an average level of zero.

26. The system of claim 25, wherein the system is configured to perform ten level pulse amplitude modulation.

27. The system of claim 25, wherein there exists 8192 symbol values reserved for data.

28. A method for shaping a constellation of symbol values for use in a communication system to create four dimensional symbol groups, the method comprising:

defining a set of symbol that comprises the constellation, wherein the symbols have absolute values that ranges between a minimum absolute value and a maximum absolute value;

defining four dimensional symbol groups from the set of symbol values to represent data, wherein the four dimensional symbol groups representing data do not comprise two or more symbol values that have a maximum absolute value;

defining four dimensional symbol groups from the constellation to represent control codes, wherein the four dimensional symbol groups representing control codes include two or more symbols having maximum absolute value symbols;

29. The method of claim 28, wherein the maximum absolute value comprises nine.

30. The method of claim 28, wherein the four dimensional symbol groups comprise sets of four symbol values selected based on data values or control code values and which are transmitted during a transmit opportunity.

31. The method of claim 28, wherein the symbol values utilized to generate the four dimensional symbol groups representing data have average value of zero.