Design and FPGA verification of a quasi-cyclic LDPC code for optical communication systems

Powerful forward error correction codes such as quasi-cyclic low density parity check (QC-LDPC) are required in next-generation coherent optical communication systems [1]. This work describes the design and experimental verification of a high net coding gain (NCG), low complexity QC-LDPC code. Towards this end, we develop a field programmable gate array (FPGA) based platform specially designed for optimization and performance evaluation of LDPC codes. The proposed FPGA framework includes several features such as the capability of changing the internal resolution of the decoder algorithm or capturing error patterns for error-floor analysis. Experimental results derived from the FPGA platform show that the designed QC-LDPC code is able to achieve an NCG of 11.6 dB at a bit-error-rate (BER) of 10
^-15
with an overhead of 25% and a codeword length of only 16K bits.