The gradient descent bit-flipping with momentum (GDBF-w/M) and probabilistic GDBF-w/M (PGDBF-w/M) algorithms significantly improve the decoding performance of the bit-flipping (BF) algorithm. In this letter, we propos...
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The gradient descent bit-flipping with momentum (GDBF-w/M) and probabilistic GDBF-w/M (PGDBF-w/M) algorithms significantly improve the decoding performance of the bit-flipping (BF) algorithm. In this letter, we propose a channel-aware GDBF-w/M algorithm which operates deterministically based on the received values from the additive white Gaussian noise (AWGN) channel. Numerical results show that the proposed algorithm does not only mitigate the error-floor phenomenon of the GDBF-w/M algorithm, but it also has better decoding performance than the PGDBF-w/M algorithm without the need for a random number generator. Furthermore, the complexity of the proposed algorithm is slightly higher than that of the GDBF-w/M algorithm.
The error correction capability of bit-flipping decoding algorithm for low density parity-check (LDPC) codes is studied by introducing variable node adjacency (VNA) graphs which are derived from Tanner graphs of LDPC ...
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ISBN:
(纸本)9781457705953
The error correction capability of bit-flipping decoding algorithm for low density parity-check (LDPC) codes is studied by introducing variable node adjacency (VNA) graphs which are derived from Tanner graphs of LDPC codes. For codes with column weight lambda and girth g - 8, it can be shown that error patterns of weight less than or equal to lambda - 1 can be corrected. This result implies that the bit-flipping algorithm could decode up to the random error-correcting capability over binary symmetric channel for girth 8 codes whose random error-correcting capability is equal to lambda - perpendicular to.
In this work, we analytically derive the evolution of single-bit messages in the bit-flipping algorithm (BFA) for irregular low-density parity-check (LDPC) codes on the binary symmetric channel (BSC). In particular, t...
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ISBN:
(纸本)9781728167589
In this work, we analytically derive the evolution of single-bit messages in the bit-flipping algorithm (BFA) for irregular low-density parity-check (LDPC) codes on the binary symmetric channel (BSC). In particular, the analysis tracks the probability distributions of the flipping functions and the bit-decision error at each iteration, which is possible by introducing a state variable at each variable node. The probability distributions are indirectly obtained by taking advantage of the state and state transition probabilities. The analysis will be confirmed by comparing analytic evaluations with simulation results. For the comparison, we implement LDPC codes at a finite length.
An escape method for the local optima of the gradient descent bit-flipping (GDBF) algorithm for decoding low-density parity-check codes is proposed. In the GDBF algorithm, a search point is likely to be trapped in a l...
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An escape method for the local optima of the gradient descent bit-flipping (GDBF) algorithm for decoding low-density parity-check codes is proposed. In the GDBF algorithm, a search point is likely to be trapped in a local optimum, which causes performance degradation of the algorithm. To address this issue, we introduce a list to store the frequency of visits to each local optimum and devise a strategy to increase the distance of a search point from a local optimum with respect to the frequency. (c) 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
In this paper, we develop the density evolution of bit-flipping algorithm (BFA) for regular low-density parity-check (LDPC) codes and analyze the evolution of probability density for the bit-decision error. In contras...
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ISBN:
(纸本)9781728108933
In this paper, we develop the density evolution of bit-flipping algorithm (BFA) for regular low-density parity-check (LDPC) codes and analyze the evolution of probability density for the bit-decision error. In contrast to the sum-product algorithm (SPA) and min-sum algorithm (MSA), the density evolution for BFA has remained untouched, which motivates this work. In the developed density evolution for BFA, we first introduce a state variable which is a function of bit-decision result and the flipping function value at each iteration. Then, the state probability is derived, with which the density of bit-decision error is obtained. To confirm the derivations, we design regular LDPC codes and compare the empirical evaluations of bit-error rates and the derived probability of bit-decision errors.
Overlapped frequency division multiplexing (OVFDM) systems can obtain high spectral effciency (SE), which is proportional to the constraint length. However, high decoding complexity imposes the main challenge on OVFDM...
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Overlapped frequency division multiplexing (OVFDM) systems can obtain high spectral effciency (SE), which is proportional to the constraint length. However, high decoding complexity imposes the main challenge on OVFDM systems. This paper proposes a low-complexity sliding window ( SW) block decoding algorithm for OVFDM systems, where data symbols are estimated based on the reception of a SW instead of a date frame. Specifically, block code of each SW is decoded by bit-flipping algorithm where the bits to be flipped are selected according to the largest absolute value criterion. Using this criterion, the complexity to obtain the near optimal bit-flipping vector grows only linearly with the SW length. In addition, the study of the decoding algorithm is based on the design of OVFDM encoding structure, where symbols can occupy orthogonal in-phase and quadrature channels simultaneously to further improve SE by a factor of two. Simulation results show that OVFDM SW decoding with bit-flipping algorithm can be used when constraint length is relatively high (constraint length >= 20) because the complexity goes roughly linearly with the increase of constraint length.
We propose a gradient descent type bitflippingalgorithm for decoding low density parity check codes on the binary symmetric channel. Randomness introduced in the bitflipping rule makes this class of decoders not on...
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We propose a gradient descent type bitflippingalgorithm for decoding low density parity check codes on the binary symmetric channel. Randomness introduced in the bitflipping rule makes this class of decoders not only superior to other decoding algorithms of this type, but also robust to logic-gate failures. We report a surprising discovery that for a broad range of gate failure probability our decoders actually benefit from faults in logic gates which serve as an inherent source of randomness and help the decoding algorithm to escape from local minima associated with trapping sets.
A novel class of bit-flipping (BF) algorithm for decoding low-density parity-check (LDPC) codes is presented. The proposed algorithms, which are referred to as gradient descent bitflipping (GDBF) algorithms, can be r...
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A novel class of bit-flipping (BF) algorithm for decoding low-density parity-check (LDPC) codes is presented. The proposed algorithms, which are referred to as gradient descent bitflipping (GDBF) algorithms, can be regarded as simplified gradient descent algorithms. The proposed algorithms exhibit better decoding performance than known BF algorithms, such as the weighted BF algorithm or the modified weighted BF algorithm for several LDPC codes.
It is known that the Gradient descent bitflipping (GDBF) algorithm is an effective hard-decision decoding algorithm for low-density parity-check (LDPC) codes. However, trapping in a local maximum limits its error-rat...
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ISBN:
(纸本)9781538604465
It is known that the Gradient descent bitflipping (GDBF) algorithm is an effective hard-decision decoding algorithm for low-density parity-check (LDPC) codes. However, trapping in a local maximum limits its error-rate performance. This paper presents a modified GDBF scheme that can mitigate the trapping problem and hence can improve the error-rate performance. Compared to the conventional GDBF algorithm, the proposed method is able to improve the decoding performance of 0.3dB for an (18582, 16626) code. The (18582, 16626) LDPC decoder integrates 636k logic gates and achieves a throughput of 12.4 Gbps at a clock frequency of 200 MHz in a 90nm process.
This brief presents three strategies, including initialization based on Look Up Table (LUT), postprocessing based on bitflipping and hard decision based on the posterior information, to reduce the number of decoding ...
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This brief presents three strategies, including initialization based on Look Up Table (LUT), postprocessing based on bitflipping and hard decision based on the posterior information, to reduce the number of decoding cycles (DCs) for stochastic low-density parity-check decoding. For the standard IEEE 802.3an code, simulation indicates a 73.6% reduction in the average number of DCs with a satisfactory bit error rate. Moreover, hardware implementation shows that the area required for the proposed decoder is significantly reduced.
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