Methods and apparatus for trellis-based modulation encoding
Methods and apparatus are provided for trellis-based modulation encoding. A signal is modulation encoded by encoding one or more blocks of the signal using one or more corresponding edges in a trellis, wherein each edge in the trellis has a corresponding bit pattern; selecting a winning path through the trellis based on at least one transition-based run-length constraint; and generating an encoded sequence using edges associated with the winning path. Exemplary trellis pruning techniques are also provided. The winning path through the trellis is selected by minimizing one or more modulation metrics.
1. A method for modulation encoding of a signal, comprising:
encoding one or more blocks of said signal using, one or more corresponding edges in a trellis, wherein each edge in said trellis has a corresponding bit pattern;
selecting a winning path through said trellis using a Viterbi algorithm based on at least one transition-based run-length constraint; and
generating an encoded sequence using edges associated with said winning path.
2. The method of claim 1 , wherein each block is encoded by scrambling said block with said one or more corresponding edges.
3. The method of claim 1 , wherein each block is encoded with said one or more corresponding edges using an exclusive OR function.
4. The method of claim 1 , further comprising the step of pruning an edge in said trellis if said edge violates a run-length constraint.
5. The method of claim 1 , wherein said Viterbi algorithm selects said winning path through said trellis by minimizing one or more modulation metrics.
6. The method of claim 5 , wherein said modulation metrics suppress one or more error events.
7. The method of claim 5 , wherein said modulation metrics assign a higher weight to longer transition runs in binary data encoded in said signal.
8. The method of claim 5 , wherein said modulation metrics are computed within a sliding window.
9. The method of claim 5 , wherein said modulation metrics assign a higher weight to transitions than to non-transitions in binary data encoded in said signal.
10. The method of claim 1 , wherein said generating step further comprises the step of inserting one or more of modulation bits and a state index.
11. The method of claim 1 , wherein each edge in said trellis has a corresponding bit pattern that is stored with a reduced number of bits and is expanded to a number of bits associated with said blocks of said signal.
12. The method of claim 1 , further comprising the step of pruning one or more edges in said trellis to reduce a path memory associated with said trellis.
13. The method of claim 12 , further comprising the step of pruning one or more edges in said trellis that were not selected by a majority voting rule.
14. A system for modulation encoding of a signal, comprising:
a memory; and
at least one processor, coupled to the memory, operative to:
encode one or more blocks of said signal using one or more corresponding edges in a trellis, wherein each edge in said trellis has a corresponding bit pattern;
select a winning path through said trellis using a Viterbi algorithm based on at least one transition-based run-length constraint; and
generate an encoded sequence using edges associated with said winning path.
15. The system of claim 14 , wherein each block is encoded by scrambling said block with said one or more corresponding edges.
16. The system of claim 14 , wherein each block is encoded with said one or more corresponding edges using an exclusive OR function.
17. The system of claim 14 , wherein said processor is further configured to prune an edge in said trellis if said edge violates a run-length constraint.
18. The system of claim 14 , wherein said V iterbi algorithm selects said winning path through said trellis by minimizing one or more modulation metrics.
19. The system of claim 18 , wherein said modulation metrics suppress one or more error events.
20. The system of claim 18 , wherein said modulation metrics assign a higher weight to longer transition runs in binary data encoded in said signal.
21. The system of claim 18 , wherein said modulation metrics are computed within a sliding window.
22. The system of claim 18 , wherein said modulation metrics assign a higher weight to transitions than to non-transitions in binary data encoded in said signal.
23. The system of claim 18 , wherein said processor is further configured to generate an encoded sequence by inserting one or more of modulation bits and a state index.
24. The system of claim 18 , wherein each edge in said trellis has a corresponding bit pattern that is stored with a reduced number of bits and is expanded to a number of bits associated with said blocks of said signal.
25. The system of claim 18 , wherein said processor is further configured to prune one or more edges in said trellis to reduce a path memory associated with said trellis.
26. The system of claim 25 , wherein said processor is further configured to prune one or more edges in said trellis that were not selected by a majority voting rule.
27. An article of manufacture for modulation encoding of a signal, comprising a non-transitory machine readable recordable medium containing one or more programs which when executed implement the steps of:
encoding one or more blocks of said signal using one or more corresponding edges in a trellis, wherein each edge in said trellis has a corresponding bit pattern;
selecting a winning path through said trellis using a Viterbi algorithm based on at least one transition-based run-length constraint; and
generating an encoded sequence using edges associated with said winning path.
28. The article of manufacture of claim 27 , wherein each block is encoded by scrambling said block with said one or more corresponding edges.
29. The article of manufacture of claim 27 , further comprising the step of pruning one or more edges in said trellis for one or more of (i) a given one of said edges violates a run-length constraint; (ii) reducing a path memory associated with said trellis; and (iii) a given one or more of said edges were not selected by a majority voting rule.
30. The article of manufacture of claim 27 , wherein said Viterbi algorithm selects said winning path through said trellis by minimizing one or more modulation metrics.
31. The article of manufacture of claim 30 , wherein said modulation metrics comprise one of more of suppressing one or more error events;
assigning a higher weight to longer transition runs in binary data encoded in said signal;
computing said modulation metrics within a sliding window and assigning a higher weight to transitions than to non-transitions in binary data encoded in said signal.
32. The article of manufacture of claim 27 , wherein said generating step further comprises the step of inserting one or more of modulation bits and a state index.
33. The article of manufacture of claim 27 , wherein each edge in said trellis has a corresponding bit pattern that is stored with a reduced number of bits and is expanded to a number of bits associated with said blocks of said signal.