Performance-Complexity Tradeoffs of Concatenated FEC for Higher-Order Modulation

Barakatain, Masoud; Lentner, Diego; Boecherer, Georg; Kschischang, Frank R.

doi:10.1109/jlt.2020.2983912

Cited by 28 publications

(24 citation statements)

References 30 publications

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“…In contrast to the structural delay, this decoding delay depends on the decoder realization and can be reduced by faster hardware. A comprehensive comparison of MLC with BICM in terms of complexity can, e.g., be found in [36], [37].…”

Section: E Comparison With Non-binary Codes and Latency Issuesmentioning

confidence: 99%

Two-Stage Coded Modulation for Hurwitz Constellations in Fiber-Optical Communications

Frey

Stern

Fischer

et al. 2020

J. Lightwave Technol.

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Four-dimensional signal constellations based on the checkerboard lattice D 4 offer a packing gain over conventional QAM constellations per polarization. Due to the increased number of nearest neighbors such power-efficient 4D formats cannot be Gray-labeled and bit-interleaved coded modulation results in a considerable performance loss. Instead, a suited coded-modulation scheme must be tailored to the properties of the underlying signal lattice. We apply a low-complexity two-stage coded-modulation scheme for constellations based on the set of Hurwitz integers, an isomorphic representation of the D 4 lattice. The proposed signaling scheme is evaluated in numerical simulations and fiber-optical system experiments. The performance is compared to a reference implementation using square QAM formats as proposed in the current 400ZR standardization activities. We demonstrate a 0.8 dB gain in required OSNR of the 512-ary Hurwitz constellation over dual-polarization 16-QAM (with 256 signal points in 4D) at the same symbol and bit rate. Additional numerical and experimental results show the potential for applications in the long-haul as well as the short-reach regime. Index Terms-Two-stage coded modulation, Hurwitz constellations, 4D modulation techniques, D 4 lattice, packing gain, bit-interleaved coded modulation, OIF 400ZR. I. INTRODUCTION T HE application of four-dimensional (4D) and higherdimensional modulation has been intensively investigated over the last decade ever since it was first introduced to the fiber-optical communications community in [1], [2]. The four orthogonal components of the electromagnetic field constitute the natural basis for 4D signal sets. It is well known that the density of signal points per unit volume can be doubled when Manuscript

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Section: E Comparison With Non-binary Codes and Latency Issuesmentioning

confidence: 99%

Two-Stage Coded Modulation for Hurwitz Constellations in Fiber-Optical Communications

Frey

Stern

Fischer

et al. 2020

J. Lightwave Technol.

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show abstract

“…A data stream encoded by the inner spatially-coupled repeat accumulate code is assigned to the low-reliability bit-levels of the constellation symbols and decoded by the two-stage MSD, while the remaining data stream bypass the inner code and are assigned to the high-reliability bit-levels of the constellation symbols. The comparison between the MSD-based MLC and BICM approach for various M-QAM modulation formats is done in [29], where the complexity-optimized soft-decision LDPC code is concatenated with the hard-decision staircase code, as in [19]. At data rate of 4.68 (bits/symbol) and applying 64-QAM modulation, the MLC scheme of [29] results in a coding gain of up to 0.4 dB or complexity savings of 60%, when compared with the BICM.…”

Section: Multilevel Codingmentioning

confidence: 99%

“…The comparison between the MSD-based MLC and BICM approach for various M-QAM modulation formats is done in [29], where the complexity-optimized soft-decision LDPC code is concatenated with the hard-decision staircase code, as in [19]. At data rate of 4.68 (bits/symbol) and applying 64-QAM modulation, the MLC scheme of [29] results in a coding gain of up to 0.4 dB or complexity savings of 60%, when compared with the BICM.…”

Section: Multilevel Codingmentioning

confidence: 99%

“…A portion L 0 of the outer encoded bits bypass the inner code and are assigned to the high-reliability bit-levels of the constellation points, while the remaining bits are protected by the inner code and are assigned to the relatively low-reliability bit-levels of the constellation points. Contrary to the MLC-based CFEC schemes proposed in [27]- [29], where the data rate is fixed for a single FEC code, our proposed scheme is capable of achieving rate flexibility with two degrees of freedom with a single FEC code by simultaneously tuning the K pc and L 0 bits.…”

Section: Multilevel Codingmentioning

confidence: 99%

“…The performance and complexity of the proposed scheme are compared to the classical BICM. The early work on fixed-rate MLC schemes date back to 1977 [26], but their application for optical fiber communication systems with concatenated codes have only recently been reported in [27]- [29], where the MLC schemes are wisely designed to offer performance or complexity savings over BICM. The novel contributions of this paper are as follows:…”

Section: Introductionmentioning

confidence: 99%

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Flexible Multilevel Coding with Concatenated Polar-Staircase Codes for M-QAM

Mehmood

Yankov

Iqbal

et al. 2020

IEEE Trans. Commun.

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In this work, a multilevel coding (MLC) based coded modulation scheme with two degrees of freedom in rate flexibility is proposed and compared with a bit-interleaved coded modulation (BICM) scheme from a performance versus complexity perspective. The proposed MLC scheme is based on a rate flexible inner soft-decision polar code and utilizes an outer hard-decision staircase code structure as in the 400ZR concatenated forward error-correcting code. The performance of the MLC scheme is investigated for a range of inner code lengths, inner decoder list sizes, and signaling with 16 and 64 quadrature amplitude modulation, respectively. The MLC is designed such that a portion of the staircase encoded bits can bypass the inner code. The number of required inner soft-decision decoders can thus be reduced, thereby saving computational complexity. The proposed MLC scheme simultaneously offers up to a 53.7% reduction in the number of inner decoders and up to 0.55 dB of performance improvement when compared with the similar BICM approach.

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Simplified Design of Multilevel Coding Scheme with Polar Codes for High-Order Modulation

Zhou

Wang

et al. 2022

Advances in Wireless Communications and Applications

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Performance-Complexity Tradeoffs of Concatenated FEC for Higher-Order Modulation

Cited by 28 publications

References 30 publications

Two-Stage Coded Modulation for Hurwitz Constellations in Fiber-Optical Communications

Two-Stage Coded Modulation for Hurwitz Constellations in Fiber-Optical Communications

Flexible Multilevel Coding with Concatenated Polar-Staircase Codes for M-QAM

Simplified Design of Multilevel Coding Scheme with Polar Codes for High-Order Modulation

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