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The Hamming(7,4) code may be written as a cyclic code over GF(2) with generator + +. In fact, any binary Hamming code of the form Ham(r, 2) is equivalent to a cyclic code, [3] and any Hamming code of the form Ham(r,q) with r and q-1 relatively prime is also equivalent to a cyclic code. [4]
Low-density parity-check (LDPC) codes are a class of highly efficient linear block codes made from many single parity check (SPC) codes. They can provide performance very close to the channel capacity (the theoretical maximum) using an iterated soft-decision decoding approach, at linear time complexity in terms of their block length.
A cyclic redundancy check (CRC) is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to digital data. [ 1 ] [ 2 ] Blocks of data entering these systems get a short check value attached, based on the remainder of a polynomial division of their contents.
The generator polynomial of the BCH code is defined as the least common multiple g(x) = lcm(m 1 (x),…,m d − 1 (x)). It can be seen that g(x) is a polynomial with coefficients in GF(q) and divides x n − 1. Therefore, the polynomial code defined by g(x) is a cyclic code.
However cyclic codes can indeed detect most bursts of length >. The reason is that detection fails only when the burst is divisible by g ( x ) {\displaystyle g(x)} . Over binary alphabets, there exist 2 ℓ − 2 {\displaystyle 2^{\ell -2}} bursts of length ℓ {\displaystyle \ell } .
The properties of this class of codes allow many users (with different codes) to use the same radio channel at the same time. To the receiver, the signals of other users will appear to the demodulator only as a low-level noise. [citation needed] Another general class of codes are the automatic repeat-request (ARQ) codes. In these codes the ...
These examples also belong to the class of linear codes, and hence they are called linear block codes. More particularly, these codes are known as algebraic block codes, or cyclic block codes, because they can be generated using Boolean polynomials. Algebraic block codes are typically hard-decoded using algebraic decoders. [jargon]
Being a code that achieves this optimal trade-off, the Reed–Solomon code belongs to the class of maximum distance separable codes. While the number of different polynomials of degree less than k and the number of different messages are both equal to q k {\displaystyle q^{k}} , and thus every message can be uniquely mapped to such a polynomial ...