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Turbo codes play an important role in making communications systems more efficient and reliable. This paper provides a description of two turbo codes algorithms. Soft-output Viterbi algorithm and logarithmic-maximum a posteriori turbo decoding algorithms are the two candidates for decoding turbo codes. Soft-input soft-output (SISO) turbo decoder based on soft-output Viterbi algorithm (SOVA) and the...
A universal design of low-density parity-check (LDPC) code ensembles which enables to operate reliably over various channels is of great interest. This paper considers the universality of LDPC code ensembles over sets of memoryless binary-input output-symmetric (MBIOS) channels, addressing their universality under belief-propagation (BP) and maximum-likelihood (ML) decoding. Based on the density evolution...
Recently, it was observed that spatially-coupled LDPC code ensembles approach the Shannon capacity for a class of binary-input memoryless symmetric (BMS) channels. The fundamental reason for this was attributed to a threshold saturation phenomena derived in. In particular, it was shown that the belief propagation (BP) threshold of the spatially coupled codes is equal to the maximum a posteriori (MAP)...
A MAP algorithm for decoding maximum transition run (MTR) codes, using the soft-decision approach, is presented in this paper. The algorithm is based on the Bayesian algorithm, and computes a posteriori log-likelihood ratio (LLR) for output bits, using codewords of the MTR code. The log MAP and max-log MAP version of the algorithm have been developed, showing performance comparable to that of the...
The asymmetric Z-channel is a discrete memoryless channel with one of the input symbols transmitted with noise. In this paper, based on the maximum a posterior probability (MAP) decoding algorithm, a novel decoding algorithm for the asymmetric Z-channel is proposed and the performance of turbo codes with the proposed algorithm is simulated. The simulation results show that the proposed turbo decoding...
An error-correction coding solution, MCU interface based (23,12,7) Golay coder and decoder for intelligent home wireless communication system in SoC realization is given. The solution presents a function module partition method, and gives an analytical method for function units based on mathematical model to illuminate the coding principle. The whole solution provides a software and hardware cooperative...
In this paper, different iterative decoders for turbo Gallager codes are optimised and compared for the binary erasure channel. The complexity and performance differences between turbo decoder, BCJR-based Look-Up Table decoder and belief propagation decoder are analysed and evaluated. A hybrid decoding arrangement, which uses an iterative decoder followed by a maximum likelihood ??In-Place?? matrix...
The low decoding complexity structure of Linear Dispersion Space Time Block Codes (LDSTBCs) with unitary weight matrices is analyzed. It is shown that given n = 2alpha, the maximum number of groups in which the information symbols can be separated and decoded independently is (2a + 2), and as we lower the number of different groups to (2k + 2), 0 les k les alpha, we get higher rate codes. We also...
In this paper we propose a mitigation technique for the protection of critical data in electronic devices from Single Error Upsets (SEU) that manifest themselves as bit-flips in memory. In order to cope with this problem, we take advantage of convolutional codes. We propose a methodology to generate a light decoder architecture considering all the possible combinations of generator polynomials of...
This paper proposes methods to improve soft-input and soft-output decoding performance of BCH codes by sum-product algorithm (SPA). A method to remove cycles of length four (RmFC) in the Tanner graph has been proposed. However, the RmFC can not realize good decoding performance for BCH codes which have more than one error correcting capability. To overcome this problem, this paper proposes two methods...
In this paper, we consider communication over the binary erasure channel (BEC) using low-density parity-check (LDPC) codes. We consider MAP decoding not using a whole Tanner graph but only a neighborhood graph of fixed depth referred to as local-MAP decoding for deriving lower bounds of the error probability under message-passing decoding and bit-flipping decoding. The main result of this paper is...
This paper explores ideas for fast linear programming (LP) decoding of low-density parity-check (LDPC) codes. We first propose a modification of adaptive LP decoding, and prove that it performs LP decoding by solving a number of linear programs that contain at most one linear constraint derived from each of the parity-check constraints. Then, as a step toward designing an efficient LP solver that...
In this paper we investigate utilization of lattice-reduction (LR) approach for MIMO decoding in multiple antenna systems. We show how to expand LR method initially designed for real value lattices into complex lattices utilized in MIMO OFDM systems. We offer the two effective schemes of MIMO decoder based on complex LR, one generating hard bit output, while the other generating soft bit output. We...
The block network error control coding, BNEC, is presented to combat error and erasure for multicast in directed acyclic networks. Aiming at reducing complexity, BNEC syndrome-based decoding and detection is introduced. Next, we propose a three-stage syndrome-based BNEC decoding, comprising error detection, finding error positions and error values. Besides considering bounded-distance decoding for...
Variable-length error-correcting codes (VLECCs) have recently received extensive attention because they can provide both compression and error-correction capabilities simultaneously. The larger free distance a VLECC has, the more redundancy the VLECC suffers from. The redundancy can be used to combat the channel noise effectively by using the technique of joint source-channel decoding (JSCD). However,...
In this paper we propose a notion of EXIT functions for LT-codes and raptor codes, and discuss some of their useful properties that can be used to design good codes. We will further use these results to derive interesting conclusions on ranks of random matrices. New expressions for the asymptotic ranks of certain classes of random binary matrices are derived and the results are compared to previously...
Li and Xia have recently investigated the design of space-time codes that achieve full spatial diversity for asynchronous cooperative communications. They show that certain of the binary space-time trellis codes derived from the Hammons-El Gamal stacking construction are delay tolerant and can be used in the multilevel code constructions by Lu and Kumar to produce delay tolerant space-time codes for...
A new construction of a full-diversity full-rate space-time block code (FDFR-STBC) is presented in this paper. The design is for 2 transmit antennas and 2 time slots. The code outperforms the previous FDFR-STBC codes in [3], [4], [5], [6] for 1 receive antenna. We reduce the decoding complexity by exploiting the algebraic structure of the code and using the hybrid maximum-likelihood interference cancellation...
Fast correlation attacks have been considerably improved recently, based on efficient decoding algorithms dedicated to very large linear codes in the case of a highly noisy channel. However, a better adaptation of these techniques to the concrete involved stream ciphers is still an open issue
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