Communications Blockset

Hamming Decoder

Decode a Hamming code to recover binary vector data

Library

Block sublibrary of Channel Coding

Description

The Hamming Decoder block recovers a binary message vector from a binary Hamming codeword vector. For proper decoding, the parameter values in this block should match those in the corresponding Hamming Encoder block.

If the Hamming 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. Also, K must equal N-M.

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.

The coding scheme uses elements of the finite field GF(2^M). You can either specify the primitive polynomial that the algorithm should use, or you can rely on the default setting:

• To use the default primitive polynomial, simply enter N and K as the first and second mask parameters, respectively. The algorithm uses gfprimdf(M) as the primitive polynomial for GF(2^M).
• To specify the primitive polynomial, enter N as the first parameter and a binary vector as the second parameter. The vector represents the primitive polynomial by listing its coefficients in order of ascending exponents. You can create primitive polynomials using the gfprimfd 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 M-degree primitive polynomial

Either the message length, which is also the output vector length; or a binary vector that represents a primitive polynomial for GF(2^M).

Pair Block

Hamming Encoder

See Also

hammgen (Communications Toolbox)

Hadamard Code Generator

Hamming Encoder