In information theory, a '''soft-decision decoder''' is a kind of decoding method – a class of algorithm used to decode data that has been encoded with an error correcting code. Whereas a hard-decision decoder operates on data that take on a fixed set of possible values (typically 0 or 1 in a binary code), the inputs to a soft-decision decoder may take on a whole range of values in-between. This extra information indicates the reliability of each input data point, and is used to form better estimates of the original data. Therefore, a soft-decision decoder will typically perform better in the presence of corrupted data than its hard-decision counterpart.<ref>{{cite book |last = Proakis |first = John |title = Digital communications |edition = 4th |year = 2001 |publisher = McGraw Hill |isbn = 0-07-118183-0 |pages = 457–460}}</ref>
Soft-decision decoders are often used in Viterbi decoders and turbo code decoders.
== See also == * Forward error correction * Soft-in soft-out decoder
== References == {{reflist}}
Category:Error detection and correction
{{Telecomm-stub}}