Iterative Decoding of

In this paper we present a study of the impact of connection schemes on the performance of iterative decoding of Generalized Parallel Concatenated block (GPCB) constructed from one step majority logic decodable (OSMLD) codes and we propose a new connection scheme for decoding them. All iterative decoding connection schemes use a soft-input soft-output threshold decoding algorithm as a component decoder. Numerical result for GPCB codes transmitted over Additive White Gaussian Noise (AWGN) channel are provided. It will show that the proposed scheme is better than Hagenauer's scheme and Lucas's scheme [1] and slightly better than the Pyndiah's scheme. Keywords—Generalized Parallel concatenated block codes, OSMLD codes, threshold decoding, iterative decoding scheme, and performance.

Applied Mathematical Sciences, 2010

In this paper we well introduce a new decoding algorithm for generalized parallel concatenated block codes(GPCB). We are interested in decoding generalized parallel concatenated block codes based on two systematic one step majority logic decoding (OSMLD) codes using a soft output version of threshold algorithm with Lucas's connexion scheme. The effects of various component codes, interleaver size (Number of sub-blocks), interleaver pattern, and the number of iterations are investigated. The simulation results show that the slope of curves and coding gain are improved by increasing the number of iterations and/or the interleaver size. Proposed decoding scheme provides a performance near the Shannon limit as it is evident from simulation results.

2007 IEEE International Symposium on Signal Processing and Information Technology, 2007

Iterative threshold decoding of product and parallel concatenated block codes based on one step majority logic decodable (OSMLD) codes has proven to perform remarkably well on AWGN channels. For these codes to be applicable in wireless environment, their performance on fading channels must be examined. The purpose of this work is to study the performance of our iterative threshold decoding algorithm on the Rayleigh fading channel. Results have shown that the slope of the bit-error rate (BER) curve is as steep as for the Gaussian channel. We also present a comparison between our results and those for convolutional turbo code in terms of BER performance.

2022 5th International Conference on Advanced Communication Technologies and Networking (CommNet)

The performance of iterative decoding algorithm for one-step majority logic decodable (OSMLD) codes is investigated. We introduce a new soft-in soft-out of APP threshold algorithm which is able to decode theses codes nearly as well as belief propagation (BP) algorithm. However the computation time of the proposed algorithm is very low. The developed algorithm can also be applied to product codes and parallel concatenated codes based on block codes. Numerical results on both AWGN and Rayleigh channels are provided. The performance of iterative decoding of parallel concatenated code (17633,8595) with rate 0.5 is only 1.8 dB away from the Shannon capacity limit at a BER of 10-5 .

setit.rnu.tn

Iterative threshold decoding of product and parallel concatenated block codes based on one step majority logic decodable (OSMLD) codes has proven to perform remarkably well on AWGN channels. For these codes to be applicable in wireless environment, their performance on fading channels must be examined. The purpose of this work is to study the performance of our iterative threshold decoding algorithm on the Rayleigh fading channel. Results have shown that the slope of the bit-error rate (BER) curve is as steep as for the Gaussian channel. We also present a comparison between our results and those for convolutional turbo code in terms of BER performance.

In this paper, the performance of serially concatenated one-step majority logic decodable (SC-OSMLD) codes is investigated. The iterative decoding process uses a soft-input soft-output threshold decoding algorithm [1] as component decoder with our proposed connection scheme 2180 Fouad Ayoub et al. [2]. The effect of various components codes, interleaver size (Number of sub-blocks), and the number of iterations are investigated. Simulation results for SC-OSMLD codes transmitted over Additive White Gaussian Noise channel(AWGN) are provided. The simulation result will show that the slope of curves and coding gain are improved by increasing the number of decoder iterations and/or the interleaver size.

IEEE Transactions on Communications, 2000

The performance of iterative decoding algorithms for multi-step majority logic decodable (MSMLD) codes of intermediate length is investigated. We introduce a new bit-flipping algorithm that is able to decode these codes nearly as well as a maximum likelihood decoder on the binary symmetric channel. MSMLD codes decoded using bit-flipping algorithms can out-perform comparable BCH codes decoded using standard algebraic decoding algorithms, at least for high bit flip rates (or low and moderate signal to noise ratios).

2012

Iterative decoding techniques have gain popularity due to their performance and their application in most communications systems. In this paper, we present a new application of our iterative decoder on the GPCB (Generalized Parallel Concatenated Block codes) which uses cyclic permutations. We introduce a new variant of the component decoder. After extensive simulation; the obtained result is very promising compared with several existing methods. We evaluate the effects of various parameters component codes, interleaver size, block size, and the number of iterations. Three interesting results are obtained; the first one is that the performances in terms of BER (Bit Error Rate) of the new constituent decoder are relatively similar to that of original one. Secondly our turbo decoding outperforms another turbo decoder for some linear block codes. Thirdly the proposed iterative decoding of GPCB-BCH (75, 51) is about 2.1dB from its Shannon limit.

IEEE Journal on Selected Areas in Communications, 1998

Iterative decoding methods have gained interest, initiated by the results of the so-called “turbo” codes. The theoretical description of this decoding, however, seems to be difficult. Therefore, we study the iterative decoding of block codes. First, we discuss the iterative decoding algorithms developed by Gallager (1962), Battail et al. (1979), and Hagenauer et al. (1996). Based on their results, we propose a decoding algorithm which only uses parity check vectors of minimum weight. We give the relation of this iterative decoding to one-step majority-logic decoding, and interpret it as gradient optimization. It is shown that the used parity check set defines the region where the iterative decoding decides on a particular codeword. We make plausible that, in almost all cases, the iterative decoding converges to a codeword after some iterations. We derive a computationally efficient implementation using the minimal trellis representing the used parity check set. Simulations illustrate that our algorithm gives results close to soft decision maximum likelihood (SDML) decoding for many code classes like BCH codes. Reed-Muller codes, quadratic residue codes, double circulant codes, and cyclic finite geometry codes. We also present simulation results for product codes and parallel concatenated codes based on block codes

In this paper, a generalization of parallel concatenated block GPCB codes based on BCH and RS codes is presented.