Density Evolution Analysis of LDPC codes with Different Receivers on Impulsive Noise Channels

Mei, Z; Johnston, M; Le, Goff, S; Chen, L

doi:10.1109/ICCChina.2015.7448605

Density Evolution Analysis of LDPC codes with Different Receivers on Impulsive Noise Channels

Lookup NU author(s): Zhen Mei, Dr Martin Johnston, Dr Stephane Le Goff, Dr Li Chen

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Abstract

In conventional communication systems, the additive noise at the receiver is usually assumed to be Gaussian distributed. However, this assumption is not always valid and examples of non-Gaussian distributed noise include power line channels, underwater acoustic channels and man-made interference. Therefore it is important to design a receiver to mitigate the effects of impulsive noise. This paper proposes a new low-complexity receiver design that closely approximates the optimal log-likelihood ratio demapper and performs well when the channel varies from slightly impulsive to very impulsive. Furthermore, we present a density evolution analysis and simulation results of (3, 6) LDPC code on additive impulsive noise channels, with symmetric alpha-stable probability density functions, employing different receivers to overcome the impulsive nature of the channels. Each receiver calculates or approximates the log-likelihood ratios of the received symbols, depending on whether they are optimal or sub-optimal respectively. The threshold signal-to-noise ratios of the LDPC code are derived to determine the start of the waterfall region of the bit-error rate performance and simulation results are presented to validate our density evolution analysis.