Emmanuel Boutillon

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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 lowdensity 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 paper deals with low-complexity algorithms for the check node processing in nonbinary LDPC decoders. After a review of the state-of-the-art, we focus on an original solution to significantly reduce the order of complexity of the Extended Min-Sum decoder at the elementary check node level. The main originality of the so-called Bubble Check 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)
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)
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)
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)
In this paper, a high accuracy gaussian noise generator emulator is defined and optimized for hardware implementation on FPGA. The proposed emulator is based on the Box-Muller method implemented by using ROMs tabulation and a random memory access. By means of accumulations, the central limit method is applied to the Box-Muller output gaussian distribution.(More)
A modified Gradient Descent Bit Flipping (GDBF) algorithm is proposed for decoding Low Density Parity Check (LDPC) codes. The algorithm, called Noisy GDBF (NGDBF) offers improvement in terms of performance by adding a random perturbation at each iteration to escape from undesirable local maxima. Both single-bit and multi-bit flipping versions of the(More)