Power Consumption for Coherent Optical Orthogonal Frequency Division Multiplexing With Punctured LDPC Codes and Variable Amplitude Block Codes

Recently, coherent optical OFDM (CO-OFDM) has been proposed in optical network to increase the transmission distance with combating chromatic dispersion. CO-OFDM system has been successfully processed and recovered for transmitted signals without chromatic dispersion compensation. However, in optical links, the available optical power is limited due to safety and power consumption. Therefore, in this paper, we focus on the minimizing the optical power and propose the CO-OFDM with punctured LDPC codes and variable amplitude block codes. In the proposed system, we consider the rate-compatible punctured code (RCPC) without erasing the coded bits corresponding to zeros in the puncturing pattern and assign them to the subcarriers. In this case, the transmission rate is not degraded compared to the original code. Moreover, the coded bits corresponding to zeros in the puncturing pattern are mapped with reduced amplitude. Therefore, it is possible to increase the transmission distance with reducing the required OSNR for satisfying the target BER.