Claims
- 1. A method for decoding comprising the steps of:
i) receiving a set of probability messages in a first format; ii) updating said set of probability messages based on an operation that compares said set of probability messages with a first-set of code constraints; iii) transforming said set updated at step ii) into a second format; iv) updating said set transformed at step iii) based on an operation that compares said set of probability messages with a second-set of code constraints complementary to said first-set; v) transforming said set updated at step iv) back into said first format; vi) repeating steps ii)-v) on said set of probability messages transformed at v) until a desired level of decoding is reached; and, vii) outputting said set of probability messages determined at step vi).
- 2. The method according to claim 1 wherein said first-set is a set of variable node descriptors and said second-set is a set of check-node descriptors.
- 3. The method according to claim 1 wherein said desired level of decoding is reached when step vi) is performed a predetermined number of times.
- 4. The method according to claim 1 wherein said desired level of coding is reached when step vi) is performed until said set of probability messages matches a valid code word.
- 5. A method for decoding comprising the steps of:
receiving a set of probability messages in a first format; updating said set of probability messages based on an operation that compares said set of probability messages with a first-set of code constraints; transforming said updated set into a second format; updating said transformed set based on an operation that compares said set of probability messages with a second-set of code constraints complementary to said first-set; transforming said updated set back into said first format; repeating said foregoing steps after said receiving step on said set of probability messages until a desired level of decoding is reached; and, outputting said set of probability messages once said desired level of decoding has been reached.
- 6. A system for decoding comprising:
an input device for receiving a set of probability messages in a first format; a first updating unit connected to said input device and for updating said set of probability messages based on an operation that compares said set of probability messages with a first-set of code constraints; a first transformation unit connected to said first updating unit and for transforming said updated set into a second format; a second updating unit connected to said first transformation unit for said set of probability messages in said second-format with a second-set of code constraints complementary to said first-set; a second transformation unit connected to said first updating unit and for transforming said set updated by said second updating unit back into said first format; and, an output device connected to said second transformation unit and operable to determine if said set of probability messages has been decoded to a desired level, said output device further operable to output said set of probability messages if said desired level of decoding has been achieved, said output device further operable to return said set of probability messages back to said input device if desired level decoding has been achieved.
- 7. The system according to claim 1 wherein said first-set is a set of variable node descriptors and said second-set is a set of check-node descriptors.
- 8. The system according to claim 6 wherein said desired level of decoding is reached when said set has been updated a predetermined number of times.
- 9. The system according to claim 8 wherein said desired level of coding is reached when said set of probability messages matches a valid code word.
- 10. A receiver operable to receive a channel carrying information intended for said receiver, said information being representable as probability messages, said receiver including the system for decoding according to claim 8.
- 11. The receiver according to claim 10 wherein said channel is a wireless channel.
- 12. The receiver according to claim 10 wherein said receiver is incorporated into an information appliance.
- 13. The receiver according to claim 10 wherein said information appliance is a wireless telephone.
- 14. The receiver according to claim 10 wherein said information appliance is a pager.
- 15. The receiver according to claim 9 wherein said channel is a wired channel.
- 16. The receiver according to claim 15 wherein said receiver is incorporated into a data storage device, and said channel interconnects said receiver and a data storage medium.
- 17. The receiver according to claim 16 wherein said data storage medium is magnetic.
- 18. The receiver according to claim 16 wherein said data storage medium is optical.
- 19. The receiver according to claim 10 wherein said probability messages represent whether a given bit received over said channel is a “1” or a “0”.
- 20. The receiver according to claim 10 wherein said probability messages represent a probability associated with a non-binary symbol received over said channel.
- 21. A system for decoding comprising:
an input means for receiving a set of probability messages in a first format; a transformation means operable to transform said probability messages between said first format and at least one additional format different from said first format. an updating means for updating said probability messages according to each respective said format, said formats chosen according to a computationally desirable format to perform said updating; an output means for outputting a decoded set of probability messages when a desired level of decoding has been achieved after at least one iteration of performing said transformations and said updates.
- 22. The system according to claim 20 wherein said first format is in a log ratio representation and said second format is in a log magnitude difference representation.
- 23. The system according to claim 20 wherein said computationally desirable formats allow said updating to be performed using a summation operation.
- 24. The system according to claim 20 wherein said transformation means includes two transformation units, each operable to transform probability messages between a pair of said formats.
- 25. The system according to claim 23 wherein said transformation means includes two updating units, each operable to updating said probability messages in each said format.
- 26. The system according to claim 20 wherein said first format can be represented according to the equation:
- 27. The system according to claim 20 wherein there are two of said formats and each format is the dual of the other format.
PRIORITY CLAIM
[0001] This application claims priority from U.S. No. 60/208,562 filed Jun. 2, 2000, the contents of which are incorporated herein by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60208562 |
Jun 2000 |
US |