Title :
On Analyzing Quasi-Cyclic LDPC Codes Over Modified Welch–Costas-Coded Optical CDMA System
Author :
Huang, Jen-Fa ; Yang, Chao-Chin ; Huang, Chun-Ming
Author_Institution :
Dept. of Electr. Eng., Nat. Cheng Kung Univ., Tainan, Taiwan
fDate :
6/15/2009 12:00:00 AM
Abstract :
A modified Welch-Costas (MWC) code family for the spectral-amplitude-coding (SAC) optical code-division multiple-access (OCDMA) system is proposed. On utilizing the property of the MWC codes, more compact coder/decoders can be realized via waveguide and fiber gratings. This system has a superior performance as compared to the previous Walsh-Hadamard-coded OCDMA system. In addition, we propose a new class of quasi-cyclic low-density parity-check (QC-LDPC) codes to improve the transmission performance over the MWC-coded OCDMA system when the data rate is high. Simulation results show that the coding gain of the proposed QC-LDPC codes is larger than that of the Reed-Solomon codes, and the performance of the MWC-coded OCDMA system can be greatly improved by these QC-LDPC codes when data rate is 2.5 Gb/s.
Keywords :
Hadamard codes; Reed-Solomon codes; code division multiple access; cyclic codes; diffraction gratings; optical fibre communication; parity check codes; MWC codes; Reed-Solomon codes; Walsh-Hadamard-coded OCDMA; Welch-Costas-coded optical CDMA system; bit rate 2.5 Gbit/s; coder-decoders; fiber gratings; optical code-division multiple-access; quasicyclic LDPC codes; spectral-amplitude coding; Low-density parity-check (LDPC) code; modified Welch–Costas (MWC) code; optical code division multiple access (OCDMA); spectral amplitude coding (SAC);
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2008.2009548
