Method and apparatus for extracting reliability information from partial response channels
AssigneeLucent Technologies Inc.
InventorsBane V. Vasic, Inkyu Lee, Jeffrey L. Sonntag
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Abstract
The present invention is a method and system for generating soft outputs by taking advantage of the fact that, in PR channels, there exists a set of error event sequences that occurs more often than others. This results in a soft output extractor with significantly lower complexity than the prior art SOVA system. Minimum distance error event sequences are identified and soft information or bit reliabilities are extracted from the PR channel based on the identified sequences. The soft information is then used by an iterative error control decoder correct errors more efficiently.
Claims19
A method of extracting reliability information for a bit of interest in a group of bits comprising a data sequence on a partial response channel, comprising the steps of:
- calculating error event likelihood values with respect to said data sequence;
- and
- deriving a bit likelihood ratio for the bit of interest from said error event likelihood values.
A method of extracting reliability information for a bit of interest in a group of bits comprising a data sequence on a partial response channel, comprising the steps of:
- calculating error event likelihood values with respect to said data sequence, said calculating step comprising at least the steps of
- compiling a first error event set comprising error event sequences;
- selecting, from said first error event set, a second error event set comprising error event sequences which affect the bit of interest;
- and
- determining the error event likelihood value of each error event sequence of said second error event set;
- and
- deriving a bit likelihood ratio for the bit of interest from said error event likelihood values.
A device for extracting reliability information for a bit of interest in a group of bits comprising a data sequence on a partial response channel, comprising:
- an error event likelihood calculator calculating error event likelihood values with respect to said data sequence;
- and
- a bit likelihood ratio calculator deriving a bit likelihood ratio for the bit of interest from said error event likelihood values.
A device for extracting reliability information for a bit of interest in a group of bits comprising a data sequence on a partial response channel, comprising:
- an error event likelihood calculator calculating error event likelihood values with respect to said data sequence, comprising:
- an error event set compiler compiling a first error event set comprising error event sequences;
- an error event set selector selecting, from said first error event set, a second error event set comprising, error event sequences which affect the bit of interest;
- and
- determination means of determining the error event likelihood value of each error event sequence of said second error event set;
- and
- a bit likelihood ratio calculator deriving a bit likelihood ratio for the bit of interest from said error event likelihood values.
Dependencies are inferred from the claim text.