Generalized low-density parity-check codes for optical communication systems

Abstract

Abstract-This paper is concerned with investigating the performance of regular and irregular, randomlike and structured generalized low-density parity-check (GLDPC) codes for long-haul transmission. The proposed GLDPC codes outperform currently known turbo and low-density parity-check (LDPC) coding schemes with comparable parameters utilized in optical communication systems. For a GLDPC coding scheme with 23.6% redundancy, the largest so far reported coding gain of at least 11 dB (at 40 Gb/s) is demonstrated.

Nonbinary LDPC codes for optical communication systems

“…The influence of optical filter of bandwidth ( -the line rate), and electrical filter of bandwidth is also considered. Simulations on other channel models (such as AWGN or chi-square) give too pessimistic predictions of BER [14]. The results for single-channel transmission ignore the influence of interchannel nonlinearities, and as such are not the subject of interest in this letter.…”

“…The -factor is additionally decreased by noise loading. The fiber parameters may be found in [14]. The precompensation of 320 ps/nm and corresponding postcompensation are also applied.…”

Linear network coding and parallel transmission increase fault tolerance and optical reach

“…In [9], an FEC codes based on block turbo code was proposed for long-haul transmission in a DWDM network. Recently, LDPC codes have been proposed which have been shown to outperform the turbo product codes in terms on improving BER performance [10]. In our approach, we neither use nor modify any FEC codes applied in the physical layer, and assume that the best possible data rate and optical reach has already been achieved in the physical layer, which we further attempt to improve by the parallel transmission of an auxiliary channel and network coding.…”

Design of Finite-Length Generalized LDPC Codes

“…LDPC codes can be further extended to generalized LDPC (GLDPC) codes [31][32][33][34][35][36][37][38][39][40][41]. GLDPC codes usually have good minimum distance properties [32,33], compared with LDPC codes, and they generally have faster convergence speed, and have better error floor behavior.…”

“…In this work, we call a GLDPC code "strict-sense" if all the CNs use the same linear code as their component codes, denoted by "sGLDPC code" [32][33][34][35][36][37], otherwise it is called a hybrid GLDPC code, denoted by "hGLDPC code" [40,41].…”