Communications Blockset

Binary Cyclic Decoder

Decode a systematic cyclic code to recover binary vector data

Library

Block sublibrary of Channel Coding

Description

The Binary Cyclic Decoder block recovers a message vector from a codeword vector of a binary systematic cyclic code. For proper decoding, the parameter values in this block should match those in the corresponding Binary Cyclic Encoder block.

If the cyclic code has message length K and codeword length N, then N must have the form 2^M-1 for some integer M greater than or equal to 3.

The input must contain exactly N elements. If it is frame-based, then it must be a column vector. The output is a vector of length K.

You can determine the systematic cyclic coding scheme in one of two ways:

• To create an [N,K] code, enter N and K as the first and second mask parameters, respectively. The block computes an appropriate generator polynomial, namely, cyclpoly(N,K,'min').
• To create a code with codeword length N and a particular degree-(N-K) binary generator polynomial, enter N as the first parameter and a binary vector as the second parameter. The vector represents the generator polynomial by listing its coefficients in order of ascending exponents. You can create cyclic generator polynomials using the cyclpoly function in the Communications Toolbox.

Dialog Box

Codeword length N

The codeword length N, which is also the input vector length.

Message length K, or generator polynomial

Either the message length, which is also the output vector length; or a binary vector that represents the generator polynomial for the code.

Pair Block

Binary Cyclic Encoder

See Also

cyclpoly (Communications Toolbox)

Bernoulli Binary Generator

Binary Cyclic Encoder