基于LDPC-OFDM编码调制在无源光网络的研究

将低密度奇偶校验码与正交频分复用相结合的编码调制方式引入到无源光网络中,并通过Optisystem和Matlab进行联合仿真,研究了基于LDPC-OFDM编码调制的PON系统的下行传输性能。结果显示,由LDPC-OFDM编码调制的信号,在无源光网络中可以实现10 Gbit·s-1的下行传输。在误码率均为10-4时,基于LDPC-OFDM编码调制的系统传输性能较未编码传输光有4.2 dB的提升。当信噪比＞2.6 dB时,Gallager构造法较Mackay构造法和BIBD构造法有更好的误码率性能,以及当信噪比＞4.6 dB时,LLR-BP及其改进译码算法能使系统性能得到改善。

Research on and Simulation of LDPC-OFDM Coded Modulation Based on Passive Optical Network

The low density parity check codes and orthogonal frequency division multiplexing are used in the passive optical network in this paper,and the downlink transmission performance of PON system based on LDPC OFDM is simulated by using Optisystem and Mablab.The results show that the 10 Gbit·s-1 LDPC OFDM coded modulation signal can be realized in the downlink transmission in passive optical network.The transmission performance of the system based on LDPC OFDM is improved by 4.2 dB over that of the uncoded modulation at the bit error rate of.When the SNR is greater than 2.6 dB,the Gallager method has better error rate performance than the Mackay method and BIBD method,and the system has better performance with LLR BP or its improved algorithm when the SNR is greater than 4.6 dB.