Nonbinary Protograph-Based LDPC Codes Based on Additive Group of Finite Field

This letter proposes a flexible construction method of nonbinary protograph-based low-density parity-check codes based on finite field additive group operation from node perspective. First, nonzero element labels of nodes are optimized by minimum distance of corresponding binary image of rows of the parity-check matrix. Then, quasi-girth calculating method is proposed to jointly optimize node permutation label so as to improve global code's minimum distance upper bound. Simulation results illustrate the excellent performance of the proposed codes with adequately selected node's value label and permuting label.