15 research outputs found
Binary Message Passing Decoding of Product-like Codes
We propose a novel binary message passing decoding algorithm for product-like
codes based on bounded distance decoding (BDD) of the component codes. The
algorithm, dubbed iterative BDD with scaled reliability (iBDD-SR), exploits the
channel reliabilities and is therefore soft in nature. However, the messages
exchanged by the component decoders are binary (hard) messages, which
significantly reduces the decoder data flow. The exchanged binary messages are
obtained by combining the channel reliability with the BDD decoder output
reliabilities, properly conveyed by a scaling factor applied to the BDD
decisions. We perform a density evolution analysis for generalized low-density
parity-check (GLDPC) code ensembles and spatially coupled GLDPC code ensembles,
from which the scaling factors of the iBDD-SR for product and staircase codes,
respectively, can be obtained. For the white additive Gaussian noise channel,
we show performance gains up to dB and dB for product and
staircase codes compared to conventional iterative BDD (iBDD) with the same
decoder data flow. Furthermore, we show that iBDD-SR approaches the performance
of ideal iBDD that prevents miscorrections.Comment: Accepted for publication in the IEEE Transactions on Communication
Binary Message Passing Decoding of Product-like Codes
We propose a novel binary message passing decoding algorithm for product-like codes based on bounded distance decoding (BDD) of the component codes. The algorithm, dubbed iterative BDD with scaled reliability (iBDD-SR), exploits the channel reliabilities and is therefore soft in nature. However, the messages exchanged by the component decoders are binary (hard) messages, which significantly reduces the decoder data flow. The exchanged binary messages are obtained by combining the channel reliability with the BDD decoder output reliabilities, properly conveyed by a scaling factor applied to the BDD decisions. We perform a density evolution analysis for generalized low-density parity-check (GLDPC) code ensembles and spatially coupled GLDPC code ensembles, from which the scaling factors of the iBDD-SR for product and staircase codes, respectively, can be obtained. For the white additive Gaussian noise channel, we show performance gains up to 0.29 dB and 0.31 dB for product and staircase codes compared to conventional iterative BDD (iBDD) with the same decoder data flow. Furthermore, we show that iBDD-SR approaches the performance of ideal iBDD that prevents miscorrections
Binary Message Passing Decoding of Product Codes Based on Generalized Minimum Distance Decoding
We propose a binary message passing decoding algorithm for product codes
based on generalized minimum distance decoding (GMDD) of the component codes,
where the last stage of the GMDD makes a decision based on the Hamming distance
metric. The proposed algorithm closes half of the gap between conventional
iterative bounded distance decoding (iBDD) and turbo product decoding based on
the Chase--Pyndiah algorithm, at the expense of some increase in complexity.
Furthermore, the proposed algorithm entails only a limited increase in data
flow compared to iBDD.Comment: Invited paper to the 53rd Annual Conference on Information Sciences
and Systems (CISS), Baltimore, MD, March 2019. arXiv admin note: text overlap
with arXiv:1806.1090
30% Reach Increase via Low-complexity Hybrid HD/SD FEC and Nonlinearity-tolerant 4D Modulation
Current optical coherent transponders technology is driving data rates
towards 1 Tb/s/{\lambda}and beyond. This trend requires both high-performance
coded modulation schemes and efficient implementation of the
forward-error-correction (FEC) decoder. A possible solution to this problem is
combining advanced multidimensional modulation formats with low-complexity
hybrid HD/SD FEC decoders. Following this rationale, in this paper we combine
two recently introduced coded modulation techniques:the geometrically-shaped
4D-64 polarization ring-switched and the soft-aided bit-marking-scaled
reliability decoder. This joint scheme enabled us to experimentally demonstrate
the transmission of 11x218 Gbit/s channels over transatlantic distances at
5.2bit/4D-sym. Furthermore, a 30% reach increase is demonstrated over PM-8QAM
and conventional HD-FEC decoding for product codes.Comment: This work has been submitted to IEEE Photonics Technology Letter
Binary Message Passing Decoding of Product Codes Based on Generalized Minimum Distance Decoding: (Invited Paper)
We propose a binary message passing decoding algorithm for product codes based on generalized minimum distance decoding (GMDD) of the component codes, where the last stage of the GMDD makes a decision based on the Hamming distance metric. The proposed algorithm closes half of the gap between conventional iterative bounded distance decoding (iBDD) and turbo product decoding based on the Chase–Pyndiah algorithm at a bit error rate of , at the expense of some increase in complexity. The proposed algorithm entails only a limited increase in data flow compared to iBDD
On Product Codes with Probabilistic Amplitude Shaping for High-Throughput Fiber-Optic Systems
Probabilistic amplitude shaping (PAS) can flexibly vary the spectral
efficiency (SE) of fiber-optic systems. In this paper, we demonstrate the
application of PAS to bit-wise hard decision decoding (HDD) of product codes
(PCs) by finding the necessary conditions to select the PC component codes. We
show that PAS with PCs and HDD yields gains up to dB and SE improvement
up to approximately bit/channel use compared to using PCs with uniform
signaling and HDD. Furthermore, we employ the recently introduced iterative
bounded distance decoding with combined reliability of PCs to improve
performance of PAS with PCs and HDD.Comment: Accepted for publication in IEEE Communications Letter
Improved Soft-aided Decoding of Product Codes with Dynamic Reliability Scores
Products codes (PCs) are conventionally decoded with efficient iterative
bounded-distance decoding (iBDD) based on hard-decision channel outputs which
entails a performance loss compared to a soft-decision decoder. Recently,
several hybrid algorithms have been proposed aimed to improve the performance
of iBDD decoders via the aid of a certain amount of soft information while
keeping the decoding complexity similarly low as in iBDD. We propose a novel
hybrid low-complexity decoder for PCs based on error-and-erasure (EaE) decoding
and dynamic reliability scores (DRSs). This decoder is based on a novel EaE
component code decoder, which is able to decode beyond the designed distance of
the component code but suffers from an increased miscorrection probability. The
DRSs, reflecting the reliability of a codeword bit, are used to detect and
avoid miscorrections. Simulation results show that this policy can reduce the
miscorrection rate significantly and improves the decoding performance. The
decoder requires only ternary message passing and a slight increase of
computational complexity compared to iBDD, which makes it suitable for
high-speed communication systems. Coding gains of up to 1.2 dB compared to the
conventional iBDD decoder are observed.Comment: Submitted to IEE
One and Two Bit Message Passing for SC-LDPC Codes with Higher-Order Modulation
Low complexity decoding algorithms are necessary to meet data rate
requirements in excess of 1 Tbps. In this paper, we study one and two bit
message passing algorithms for belief propagation decoding of low-density
parity-check (LDPC) codes and analyze them by density evolution. The variable
nodes (VNs) exploit soft information from the channel output. To decrease the
data flow, the messages exchanged between check nodes (CNs) and VNs are
represented by one or two bits. The newly proposed quaternary message passing
(QMP) algorithm is compared asymptotically and in finite length simulations to
binary message passing (BMP) and ternary message passing (TMP) for spectrally
efficient communication with higher-order modulation and probabilistic
amplitude shaping (PAS). To showcase the potential for high throughput forward
error correction, spatially coupled LDPC codes and a target spectral efficiency
(SE) of 3 bits/QAM symbol are considered. Gains of about 0.7 dB and 0.1 dB are
observed compared to BMP and TMP, respectively. The gap to unquantized belief
propagation (BP) decoding is reduced to about 0.75 dB. For smaller code rates,
the gain of QMP compared to TMP is more pronounced and amounts to 0.24 dB in
the considered example.Comment: Accepted for IEEE/OSA Journal on Lightwave Technolog