title: Analysis of soft-decision FEC on non-AWGN channels.
abstract: Soft-decision forward error correction (SD-FEC) schemes are typically designed for additive white Gaussian noise (AWGN) channels. In a fiber-optic communication system, noise may be neither circularly symmetric nor Gaussian, thus violating an important assumption underlying SD-FEC design. This paper quantifies the impact of non-AWGN noise on SD-FEC performance for such optical channels. We use a conditionally bivariate Gaussian noise model (CBGN) to analyze the impact of correlations among the signal's two quadrature components, and assess the effect of CBGN on SD-FEC performance using the density evolution of low-density parity-check (LDPC) codes. On a CBGN channel generating severely elliptic noise clouds, it is shown that more than 3 dB of coding gain are attainable by utilizing correlation information. Our analyses also give insights into potential improvements of the detection performance for fiber-optic transmission systems assisted by SD-FEC.
authors.affiliation: Bell Labs, Alcatel-Lucent, 1649 Sangam-Dong, Mapo-Gu, Seoul 121-904, South Korea. junho.cho@alcatel-lucent.com
authors.forename: Junho
authors.initials: J
authors.lastname: Cho
authors.forename: Chongjin
authors.initials: C
authors.lastname: Xie
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Winzer
mesh_terms: D016477:Artifacts; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D008962:Models, Theoretical; D055096:Optical Devices; D012542:Scattering, Radiation; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013685:Telecommunications / Q000295:instrumentation*