coding theory Coding theory is the study of the properties of codes and their respective fitness for specific applications. Codes are used for data compression, cryptography, error detection and correction, data transmission and data storage. Codes are stud ...

, a coset leader is a

word A word is a basic element of language that carries an semantics, objective or pragmatics, practical semantics, meaning, can be used on its own, and is uninterruptible. Despite the fact that language speakers often have an intuitive grasp of w ...

of minimum weight in any particular

coset In mathematics, specifically group theory, a subgroup of a group may be used to decompose the underlying set of into disjoint, equal-size subsets called cosets. There are ''left cosets'' and ''right cosets''. Cosets (both left and right) ...

- that is, a word with the lowest amount of non-zero entries. Sometimes there are several words of equal minimum weight in a coset, and in that case, any one of those words may be chosen to be the coset leader. Coset leaders are used in the construction of a

standard array In coding theory, a standard array (or Slepian array) is a q^ by q^ array that lists all elements of a particular \mathbb_q^n vector space. Standard arrays are used to decode linear codes; i.e. to find the corresponding codeword for any received vec ...

for a

linear code In coding theory, a linear code is an error-correcting code for which any linear combination of codewords is also a codeword. Linear codes are traditionally partitioned into block codes and convolutional codes, although turbo codes can be seen as ...

, which can then be used to decode received vectors. For a received vector ''y'', the decoded message is ''y - e'', where ''e'' is the coset leader of ''y''. Coset leaders can also be used to construct a fast decoding strategy. For each coset leader ''u'' we calculate the syndrome ''uH′''. When we receive ''v'' we evaluate ''vH′'' and find the matching

syndrome A syndrome is a set of medical signs and symptoms which are correlated with each other and often associated with a particular disease or disorder. The word derives from the Greek σύνδρομον, meaning "concurrence". When a syndrome is paired ...

. The corresponding coset leader is the most likely error pattern and we assume that ''v''+''u'' was the codeword sent.

References

* Coding theory Error detection and correction {{crypto-stub