Non-Binary Serial Turbo LDPC Codes Combined with High Order Constellations
Résumé
Given the increasing number of applications requiring high data transmission, this is the reason for the use of high order constellations such as Quadrature Amplitude Modulation (QAM). However, communication systems using QAM require a high signal to noise ratio. To overcome this disadvantage, it is interesting to combine high error correction codes such as Low-Density Parity-Check (LDPC) codes with QAM. Although the LDPC codes are good codes for a system using QAM, concatenation of these codes with iterative decoding is still attractive to construct more powerful codes. In this context, we propose the non-binary serial turbo LDPC code. It is obtained by a serial combination of two identical regular non-binary LDPC codes, separated by an interleaver introducing the diversity. Regular codes were used to avoid the complexity of irregular codes despite that they have better performance than the regular code. Simulation results show that the performance of non-binary serial turbo LDPC code, with 16-QAM, 64-QAM and 256-QAM constellations using Gray mapping under Gaussian and Rayleigh channels, are higher than that of nonbinary LDPC codes.