Girth conditioning of LDPC codes through modified breadth first search algorithm

This paper proposes a method to improve the performance of a low-density parity-check code, by selectively removing some cycles from the associated bipartite graph. The method is based on a modified version of breadth-first search (BFS) algorithm, that we call modified BFS (MBFS). Throughout the paper we will give a detailed description of the algorithm and analytically study its complexity. Simulation results will show that applying MBFS to a given code leads to significant improvement of its performance.