Abstract
Different constructions of LDPC codes based on
matrix equations are investigated. The parameters such as the
dimension, rate and distance are computed. The classical Tanner
graph representation known for LDPC codes are described.
The main difference between standard LDPC codes and the
LDPC codes based on matrix equations lies in the structure of
their codewords. Whereas in the classical situation codewords
are simply vectors, the codewords in this new setting will
be two-dimensional vectors or matrices. This implies that the
parity-check constraints must be satisfied in both perpendicular
directions of the codeword. Therefore, a codeword may be
interpreted as a two-dimensional array which is suitable for
recording on two-dimensional pattern-oriented storage media