Non-Binary Parallel Turbo LDPC Codes Associated with High Order Constellation
Résumé
Since the non-binary LDPC (Low-Density Parity-Check) codes offer better performance than binary LDPC codes for a system using high order constellations such as the QAM (Quadrature Amplitude Modulation), one proposes in this paper a high non-binary LDPC code, called a parallel nonbinary turbo LDPC code. It is obtained by a parallel concatenation of two identical regular non-binary LDPC codes, separated by an interleaver introducing the diversity through the turbo-code structure proposed by Berrou and others. Regular codes were used to avoid the complexity of irregular codes despite that they have better performance than the regular code. In our simulation, we evaluate overRayleigh and Gaussian channels, the performance of the proposed code combined with a 16-QAMusing Gray mapping. We show that the parallel non-binary turbo LDPC code outperforms a single non-binary LDPC code, with the same code length and code rate. Also, we note that its performance can be improved with the increase of two numbers of iterations: global iterations and iterations of non-binary LDPC codes.