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—A unified framework is presented in order to build lattice constellations matched to both the Rayleigh fading channel and the Gaussian channel. The method encompasses the situations where the interleaving is done on the real components or on two-dimensional signals. In the latter case, a simple construction of lattices congruent to the densest binary(More)
In this paper, the decoding of low-density parity-check (LDPC) codes is considered. A new algorithm, named λ−Min algorithm, for updating extrinsic information is proposed. The λ−Min algorithm offers different trade-off performance versus complexity between the belief propagation (BP) algorithm (optimal but complex) and the universal most powerful (UMP)(More)
This tutorial paper gives an overview of the implementation aspects related to turbo decoders, where the term turbo generally refers to iterative decoders intended for Parallel Concatenated Convolutional Codes as well as for Serial Concatenated Convolutional Codes. We start by considering the general structure of iterative decoders, and the main features of(More)
A hardware White Gaussian Noise Generator (WGNG) is developed for mobile communication channel emulation in FPGA circuit. High accuracy, fast and low-cost hardware are reached by combining the Box-Muller and Central limit methods. The performance of the designed model is investigated using MATLAB. The Complexity and the performance level are given for some(More)
The main problem concerning the hardware implementation of turbo codes is the lack of parallelism in the MAP-based decoding algorithm. This paper proposes to overcome this problem with a new family of turbo codes, named Slice Turbo Codes. This family is based on two ideas: the encoding of each dimension with P independent tail-biting codes and a constrained(More)
This paper presents several techniques for the VLSI implementation of the MAP algorithm. In general, knowledge about the implementation of the Viterbi algorithm can be applied to the MAP algorithm. Bounds are derived for the dynamic range of the state metrics which enable the designer to optimize the word length. The computational kernel of the algorithm is(More)
This paper presents a method for designing a high accuracy white gaussian noise generator suitable for communication channel emulation. The proposed solution is based on the combined use of the Box-Muller method and the central limit theorem. The resulting architecture provides a high accuracy AWGN with a low complexity architecture for a digital(More)
| Through a rapid survey of the architecture of Low-Density Parity-Check (LDPC) decoders, this paper proposes a general framework to describe and compare LDPC decoder architectures. A set of parameters makes it possible to classify the scheduling of iterative decoders, memory organization and type of check node processors and variable node processors. Using(More)
—Layered decoding is known to provide efficient and high-throughput implementation of LDPC decoders. However, the implementation of the layered architecture is not always straightforward because of the memory access conflicts in the a-posteriori information memory. In this paper, we focus our attention on a particular type of conflict introduced by the(More)