Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1505.05405 · IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)

Spatially coupled codes and optical fiber communications: An ideal match?

Laurent Schmalen, Detlef Suikat, Detlef Rösener, Vahid Aref, A. Leven, Stephan ten Brink

Published Jun 1, 2015• 14 citations
arXivHTMLPDF

Abstract

In this paper, we highlight the class of spatially coupled codes and discuss their applicability to long-haul and submarine optical communication systems. We first demonstrate how to optimize irregular spatially coupled LDPC codes for their use in optical communications with limited decoding hardware complexity and then present simulation results with an FPGA-based decoder where we show that very low error rates can be achieved and that conventional block-based LDPC codes can be outperformed. In the second part of the paper, we focus on the combination of spatially coupled LDPC codes with different demodulators and detectors, important for future systems with adaptive modulation and for varying channel characteristics. We demonstrate that SC codes can be employed as universal, channel-agnostic coding schemes.

DOI
10.1109/spawc.2015.7227080

Related papers

LDPC Codes Derived from Quasi-cyclic Code Design Suitable for Optical Communications

Xiaole Sun, Ivan B. Djordjević

We propose a rate-adaptive forward error correction (FEC) scheme based on spatially-coupled (SC) LDPC codes derived from quasi-cyclic (QC) LDPC codes with its field-programmable gate array (FPGA) architecture. By FPGA emulation, we show that, with comparable computational complexity, the proposed LDPC codes provide larger coding gain and smaller error floor compare to the QC-LDPC base code. As a result, due to its hardware friendly structure, they are presented to be a promising candidate for the next-generation intelligent optical communication systems such as long-haul optical transmission system.

International Conference on Transparent Optical Networks•Jul 1, 2018•3 citations

FPGA implementation of rate-adaptive spatially coupled LDPC codes suitable for optical communications

Xiaole Sun, Ivan B. Djordjević

In this paper, we propose a unified field-programmable gate array (FPGA) structure for a rate-adaptive forward error correction (FEC) scheme based on spatially coupled (SC) LDPC codes derived from quasi-cyclic (QC) LDPC codes. We described the unified decoder structure in detail and showed that the rate adaptation can be achieved by a controller on-the-fly. By FPGA based emulation, the results show that, with comparable complexity, the SC codes provide larger coding gain. The implemented unified structure can be employed for any template QC-LDPC code to achieve a spatially-coupling based code-rate adaptation scheme.

Optics Express•Jan 31, 2019•11 citations

Asymptotic and finite-length performance of irregular spatially-coupled codes

Reza A. Ashrafi, Abdullah Sarıduman, Alí Emre Pusane

The newest family of low-density parity-check (LDPC) codes, spatially-coupled (SC) codes, is shown to have several desirable characteristics including low implementation complexity and close-to-optimal performance over a range of channels. Furthermore, because of their ribbon-shaped parity-check matrices, window decoding can be used to decode these codes, which leads to low-delay implementations. Researchers have focused on asymptotically regular SC code ensembles and have examined several aspects of the code construction processes. In this paper, we concentrate on irregular SC code ensembles. We evaluate their decoding thresholds over the binary erasure channel and show that their performance is better than their regular SC counterparts. It is also shown that the gap between asymptotic coding thresholds of irregular SC ensembles and the fundamental Shannon limit gets negligibly small. For the sake of a better comparison, we have also evaluated the finite-length error performance of selected regular and irregular SC codes over the additive white Gaussian channel and it is also observed that finite-length error performance of these irregular SC codes outperforms regular SC codes. To further improve the error performance of these codes and to lower the possible error floors, progressive edge growth algorithm has also been considered in the finite-length performance analysis.

IEEE International Black Sea Conference on Communications and Networking•May 1, 2014•1 citation

Affine Geometry Low-density Parity Check Codes in Long-haul Optical Communications

Bane V. Vasic, Ivan B. Djordjević

In this paper we investigate the performance of low-density parity-check (LDPC) codes in long haul optical communication systems. We are particularly concerned with high-rate codes on affine geometries. These codes have large minimum distance and simple iterative decoding algorithm, which makes them good candidates for high-speed applications such as optical communications. We consider both the bit-flipping iterative decoding and iterative decoding based on min-sum algorithm. We demonstrate a significant performance improvement with respect to the state-of-the-art error control schemes employed in long-haul systems for different signal formats (NRZ, RZ, CRZ). Contrary to the common practice of considering the error controlling schemes using the AWGN channel assumption, we consider the performance of the proposed LDPC schemes taking into account in a natural way all major impairments in a long-haul optical transmission such as ASE noise, pulse distortion due to fiber nonlinearities, chromatic dispersion or polarization dispersion, crosstalk effects, intersymbol-interference, etc.

Journal of Optical Communications•Jun 1, 2002•1 citation

Spatially coupled LDPC-BCH codes in quantum secure direct communications

Wang Ping, Zhen Sun, Liuguo Yin +1 more

Quantum secure direct communication systems are limited by high erasure probabilities and low receiving probabilities due to the high light source losses in the optical elements and optical fibers. A channel mitigation method based on spatially coupled LDPC-BCH codes is presented here to ensure reliable information transformations in quantum secure direct communication systems to resolve the problems of low-rate and Shannon limit-approaching code designs. Spatially coupled LDPC-BCH codes are constructed by coupling multiple identical block LDPC-BCH codes with edge spreading. The extrinsic information transfer functions of the spatially coupled LDPC-BCH code are analyzed to derive the decoding thresholds for the code ensembles. Simulations show that the spatially coupled LDPC-BCH codes have decoding thresholds closer to the Shannon limit with lower bit error rates than block LDPC-BCH codes. The spatially coupled LDPC-BCH code channel mitigation scheme has a transmitting efficiency of 0.001 and a bit error rate less than 10 −6 when the channel receiving probability is set at 0.4%. 摘要 受光源、光器件和光纤损耗影响, 量子安全直接通信系统的信息传输面临删除概率极大、接收概率极低的难题。为保证量子安全直接通信系统信息传输的可靠性, 该文提出了基于空间耦合LDPC-BCH码的信道补偿方案, 解决了极低码率码字构造和逼近Shannon限实用码字设计2方面的问题。将多个相同的分组LDPC-BCH码通过边连接的方式耦合起来构造得到了空间耦合LDPC-BCH码。建立了空间耦合LDPC-BCH码集的外信息转移函数, 并基于外信息转移函数分析了码集的译码门限值。仿真结果表明：与分组LDPC-BCH码相比, 空间耦合LDPC-BCH码的译码门限更接近Shannon限, 误比特率更低。在信道接收概率为0.4%时, 采用传输效率为0.001的空间耦合LDPC-BCH码信道补偿方案, 系统误比特率低于10 -6 。

Journal of Tsinghua University(Science and Technology)•Sep 15, 2019•2 citations

An Efficient Encoding Method for Spatially Coupled Low-Density Parity-Check Codes

Zhanji Wu, Min Zhao, Shuoshuo Wang

In this paper, an efficient encoding scheme for spatially coupled low-density parity-check (SC-LDPC) codes is proposed. In order to lower the error floor, we optimize the degree distribution of SC-LDPC codes and propose a split variable nodes algorithm constructing sub-matrices with large girth of SC-LDPC codes. The corresponding sliding window decoding is studied as well to fasten the decoding convergence. Simulation results show that on the AWGN channel, SC-LDPC codes can obtain better error performance, lower decoding complexity and faster decoding convergence as compared with the LDPC block codes (LDPC-BC).

IEEE International Conference on Computer and Communications (ICCC)•Dec 1, 2019•0 citations
In this paper, we highlight the class of spatially coupled codes and discuss their applicability to long-haul and submarine optical communication systems. We first demonstrate how to optimize irregular spatially coupled LDPC codes for their use in optical communications with limited decoding hardware complexity and then present simulation results with an FPGA-based decoder where we show that very low error rates can be achieved and that conventional block-based LDPC codes can be outperformed. In the second part of the paper, we focus on the combination of spatially coupled LDPC codes with different demodulators and detectors, important for future systems with adaptive modulation and for varying channel characteristics. We demonstrate that SC codes can be employed as universal, channel-agnostic coding schemes.
We propose a rate-adaptive forward error correction (FEC) scheme based on spatially-coupled (SC) LDPC codes derived from quasi-cyclic (QC) LDPC codes with its field-programmable gate array (FPGA) architecture. By FPGA emulation, we show that, with comparable computational complexity, the proposed LDPC codes provide larger coding gain and smaller error floor compare to the QC-LDPC base code. As a result, due to its hardware friendly structure, they are presented to be a promising candidate for the next-generation intelligent optical communication systems such as long-haul optical transmission system.
In this paper, we propose a unified field-programmable gate array (FPGA) structure for a rate-adaptive forward error correction (FEC) scheme based on spatially coupled (SC) LDPC codes derived from quasi-cyclic (QC) LDPC codes. We described the unified decoder structure in detail and showed that the rate adaptation can be achieved by a controller on-the-fly. By FPGA based emulation, the results show that, with comparable complexity, the SC codes provide larger coding gain. The implemented unified structure can be employed for any template QC-LDPC code to achieve a spatially-coupling based code-rate adaptation scheme.
The newest family of low-density parity-check (LDPC) codes, spatially-coupled (SC) codes, is shown to have several desirable characteristics including low implementation complexity and close-to-optimal performance over a range of channels. Furthermore, because of their ribbon-shaped parity-check matrices, window decoding can be used to decode these codes, which leads to low-delay implementations. Researchers have focused on asymptotically regular SC code ensembles and have examined several aspects of the code construction processes. In this paper, we concentrate on irregular SC code ensembles. We evaluate their decoding thresholds over the binary erasure channel and show that their performance is better than their regular SC counterparts. It is also shown that the gap between asymptotic coding thresholds of irregular SC ensembles and the fundamental Shannon limit gets negligibly small. For the sake of a better comparison, we have also evaluated the finite-length error performance of selected regular and irregular SC codes over the additive white Gaussian channel and it is also observed that finite-length error performance of these irregular SC codes outperforms regular SC codes. To further improve the error performance of these codes and to lower the possible error floors, progressive edge growth algorithm has also been considered in the finite-length performance analysis.
In this paper we investigate the performance of low-density parity-check (LDPC) codes in long haul optical communication systems. We are particularly concerned with high-rate codes on affine geometries. These codes have large minimum distance and simple iterative decoding algorithm, which makes them good candidates for high-speed applications such as optical communications. We consider both the bit-flipping iterative decoding and iterative decoding based on min-sum algorithm. We demonstrate a significant performance improvement with respect to the state-of-the-art error control schemes employed in long-haul systems for different signal formats (NRZ, RZ, CRZ). Contrary to the common practice of considering the error controlling schemes using the AWGN channel assumption, we consider the performance of the proposed LDPC schemes taking into account in a natural way all major impairments in a long-haul optical transmission such as ASE noise, pulse distortion due to fiber nonlinearities, chromatic dispersion or polarization dispersion, crosstalk effects, intersymbol-interference, etc.
Quantum secure direct communication systems are limited by high erasure probabilities and low receiving probabilities due to the high light source losses in the optical elements and optical fibers. A channel mitigation method based on spatially coupled LDPC-BCH codes is presented here to ensure reliable information transformations in quantum secure direct communication systems to resolve the problems of low-rate and Shannon limit-approaching code designs. Spatially coupled LDPC-BCH codes are constructed by coupling multiple identical block LDPC-BCH codes with edge spreading. The extrinsic information transfer functions of the spatially coupled LDPC-BCH code are analyzed to derive the decoding thresholds for the code ensembles. Simulations show that the spatially coupled LDPC-BCH codes have decoding thresholds closer to the Shannon limit with lower bit error rates than block LDPC-BCH codes. The spatially coupled LDPC-BCH code channel mitigation scheme has a transmitting efficiency of 0.001 and a bit error rate less than 10 −6 when the channel receiving probability is set at 0.4%. 摘要 受光源、光器件和光纤损耗影响, 量子安全直接通信系统的信息传输面临删除概率极大、接收概率极低的难题。为保证量子安全直接通信系统信息传输的可靠性, 该文提出了基于空间耦合LDPC-BCH码的信道补偿方案, 解决了极低码率码字构造和逼近Shannon限实用码字设计2方面的问题。将多个相同的分组LDPC-BCH码通过边连接的方式耦合起来构造得到了空间耦合LDPC-BCH码。建立了空间耦合LDPC-BCH码集的外信息转移函数, 并基于外信息转移函数分析了码集的译码门限值。仿真结果表明：与分组LDPC-BCH码相比, 空间耦合LDPC-BCH码的译码门限更接近Shannon限, 误比特率更低。在信道接收概率为0.4%时, 采用传输效率为0.001的空间耦合LDPC-BCH码信道补偿方案, 系统误比特率低于10 -6 。
In this paper, an efficient encoding scheme for spatially coupled low-density parity-check (SC-LDPC) codes is proposed. In order to lower the error floor, we optimize the degree distribution of SC-LDPC codes and propose a split variable nodes algorithm constructing sub-matrices with large girth of SC-LDPC codes. The corresponding sliding window decoding is studied as well to fasten the decoding convergence. Simulation results show that on the AWGN channel, SC-LDPC codes can obtain better error performance, lower decoding complexity and faster decoding convergence as compared with the LDPC block codes (LDPC-BC).