非规则LDPC码与PPM调制的迭代译码

The paper verification in the atmosphere of fso LDPC code and PPM modulating iterative decoding with irregular LDPC code performance is superior to the rules LDPC code. First introduces PPM modulation and demodulation, and then the basic knowledge of LDPC code introduced. In the code length and code rate, the iteration number through the simulation for LDPC code coding and decoding algorithm suitable parameters to below application. Finally in weak turbulence channel of LDPC code and PPM modulation compared simulation. The simulation results show that in the LDPC code decoding and PPM demodulation between the iterative decoding performance is superior to do not use iterative decoding and encoding irregular LDPC code when the performance of LDPC code is superior to rules.