In this paper, we derive the maximum likelihood (ML) performance for low-density parity check (LDPC) codes, considering BPSK and QPSK transmission over a Gaussian channel. We compare the theoretical ML performance with the performance of the iterative decoding algorithm. It turns out that the performance of the iterative decoding algorithm is close to the ML performance when the girth of the co...

Iterative decoding techniques have become a viable alternative for constructing high performance coding systems. In particular, the recent success of turbo codes indicates that performance close to the Shannon limit may be achieved. In this thesis, it is showed that many iterative decoding algorithms are special cases of two generic algorithms, the min-sum and sum-product algorithms, which also...

We propose a new decoding algorithm of LDPC codes over the binary erasure channel (BEC). The proposed decoding algorithm is an iterative one which uses the sparseness structure of the parity-check matrix of LDPC codes. We show by simulation results that the proposed decoding algorithm and the conventional decoding algorithm have a trade-off between remaining erasure rate and complexity. Keyword...

This paper proposes iterative demodulation/decoding for parallel combinatorial spread spectrum (PC/SS) systems. A PC/SS system conveys information data by a combination of pre-assigned orthogonal spreading sequences with polarity. In this paper, convolutional coding with a uniform random interleaver is implemented in channel coding, just like as a serial concatenated coding. A ‘soft-in/soft-out...

In this paper, the use of a reliabilitybased decoding algorithm for some concatenated codes with an interleaver, known as turbo-like codes, is examined to address and overcome the suboptimality of iterative decoding. Simulation results show that the suboptimality of iterative decoding for moderate length codes can be at least partially compensated by this combined approach. Some insights about ...

This paper focuses on a new class of flexible hybrid concatenated codes which are able to achieve any desired bit error rate performance between that of a parallel and serial concatenated convolutional code. The main contribution of this paper is a convergence analysis of the decoder, which is facilitated by an alternative representation of the code structure and an extrinsic information (EXIT)...

The so-called min-sum algorithm has been applied for decoding lattices constructed by Construction D ′ . We generalize this iterative decoding algorithm to decode lattices constructed by Construction D. An upper bound on the decoding complexity per iteration, in terms of coding gain, label group sizes of the lattice and other factors is derived. We show that iterative decoding of LDGM lattices ...

In this paper, we construct parity-concatenated trellis codes in which a trellis code is used as the inner code and a simple parity-check code is used as the outer code. From the Tanner–Wiberg–Loeliger (TWL) graph representation, several iterative decoding algorithms can be derived. However, since the graph of the parity-concatenated code contains many short cycles, the conventional min-sum and...