Laurent Schmalen

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—Spatially coupled low-density parity-check codes show an outstanding performance under the low-complexity belief propagation (BP) decoding algorithm. They exhibit a peculiar convergence phenomenon above the BP threshold of the underlying non-coupled ensemble, with a wave-like convergence propagating through the spatial dimension of the graph, allowing to(More)
—Audio-visual source encoders for digital wireless communications extract parameter sets on a frame-by-frame basis. Due to delay and complexity constraints these parameters exhibit some residual redundancy which manifests itself in non-uniform parameter distributions and intra-as well as inter-frame correlation. This residual redundancy can be exploited by(More)
We implemented a flexible transmission system operating at adjustable data rate and fixed bandwidth, baudrate, constellation and overhead using probabilistic shaping. We demonstrated in a transmission experiment up to 15% capacity and 43% reach increase versus 200 Gbit/s 16-QAM. Introduction Future optical metro and long-haul networks require transceivers(More)
— We address the optimization of joint source-channel coding schemes for iterative source-channel decoding of first-order Markov sources. Compared to the traditional design, we propose two novelties: (1) source encoders, providing code words with a minimum Hamming distance dmin ≥ 2, realized by linear block codes, and (2) irregular channel encoders which(More)
In this paper, we present a novel near-lossless compression scheme for scalar-quantized source codec parameters. The scheme is comparable to a Turbo source coding approach and can inherently incorporate protection against transmission errors. We show that using the concept of EXIT charts and irregular codes, a linear programming optimization problem can be(More)
—Iterative source-channel decoding (ISCD) exploits the residual redundancy of source codec parameters by using the Turbo principle. A powerful improvement for ISCD is the concept of redundant index assignments. In this letter we present new design and optimization guidelines for redundant index assignments. For block code based redundant index assignments,(More)
—Source codec parameters determined by modern source encoders are usually very sensitive to noise on the transmission link. Natural residual redundancy of these parameters can be utilized by Soft Decision Source Decoding (SDSD) [1] to increase the error resistance. Serially concatenating Forward Error Correction (FEC) and SDSD leads to a Iterative(More)
Low-Density Parity-Check (LDPC) codes are very powerful channel coding schemes with a broad range of applications. The existence of low complexity (i.e., linear time) iterative message passing decoders with close to optimum error correction performance is one of the main strengths of LDPC codes. It has been shown that the performance of these decoders can(More)
—In this paper, we compare different metrics to predict the error rate of optical systems based on nonbinary forward error correction (FEC). It is shown that the correct metric to predict the performance of coded modulation based on nonbinary FEC is the mutual information. The accuracy of the prediction is verified in a detailed example with multiple(More)