Design and implementation of log domain decoder

Low-Density-Parity-Check (LDPC) code has become famous in communications systems for error correction, as an advantage of the robust performance in correcting errors and the ability to meet all the requirements of the 5G system. However, the mot challenge faced researchers is the hardware implementation, because of higher complexity and long run-time. In this paper, an efficient and optimum design for log domain decoder has been implemented using Xilinx system generator with FPGA device Kintex 7 (XC7K325T-2FFG900C). Results confirm that the proposed decoder gives a Bit Error Rate (BER) very closed to theory calculations which illustrate that this decoder is suitable for next generation demand which needs high data rate with very low BER

FPGA implementation of LDPC soft-decision decoders based DCSK for spread spectrum applications

Spread spectrum (SS) communications have attracted interest because of their channel attenuation immunity and low intercept potential. Apart from some extra features such as basic transceiver structures, chaotic communication would be the analog alternative to digital SS systems. Differential chaos shift keying (DCSK) systems, non-periodic and random characteristics among chaos carriers as well as their interaction with soft data are designed based on low-density parity-check (LDPC) codes in this brief. Because of simple structure, and glorious ability to correct errors. Using the Xilinx kintex7 FPGA development kit, we investigate the hardware performance and resource requirement tendencies of the DCSK communication system based on LDPC decoding algorithms (Prob. Domain, Log Domain and Min-Sum) over AWGN channel. The results indicate that the proposed system model has substantial improvements in the performance of the bit error rate (BER) and the real-time process. The Min-Sum decoder has relatively fewer FPGA resources than the other decoders. The implemented system will achieve 10-4 BER efficiency with 5 dB associate Eb/No as a coding gain

A Tutorial on Coding Methods for DNA-based Molecular Communications and Storage

Exponential increase of data has motivated advances of data storage technologies. As a promising storage media, DeoxyriboNucleic Acid (DNA) storage provides a much higher data density and superior durability, compared with state-of-the-art media. In this paper, we provide a tutorial on DNA storage and its role in molecular communications. Firstly, we introduce fundamentals of DNA-based molecular communications and storage (MCS), discussing the basic process of performing DNA storage in MCS. Furthermore, we provide tutorials on how conventional coding schemes that are used in wireless communications can be applied to DNA-based MCS, along with numerical results. Finally, promising research directions on DNA-based data storage in molecular communications are introduced and discussed in this paper

Device-Independent Quantum Key Distribution

Cryptographic key exchange protocols traditionally rely on computational conjectures such as the hardness of prime factorisation to provide security against eavesdropping attacks. Remarkably, quantum key distribution protocols like the one proposed by Bennett and Brassard provide information-theoretic security against such attacks, a much stronger form of security unreachable by classical means. However, quantum protocols realised so far are subject to a new class of attacks exploiting implementation defects in the physical devices involved, as demonstrated in numerous ingenious experiments. Following the pioneering work of Ekert proposing the use of entanglement to bound an adversary's information from Bell's theorem, we present here the experimental realisation of a complete quantum key distribution protocol immune to these vulnerabilities. We achieve this by combining theoretical developments on finite-statistics analysis, error correction, and privacy amplification, with an event-ready scheme enabling the rapid generation of high-fidelity entanglement between two trapped-ion qubits connected by an optical fibre link. The secrecy of our key is guaranteed device-independently: it is based on the validity of quantum theory, and certified by measurement statistics observed during the experiment. Our result shows that provably secure cryptography with real-world devices is possible, and paves the way for further quantum information applications based on the device-independence principle.Comment: 5+1 pages in main text and methods with 4 figures and 1 table; 37 pages of supplementary materia

Cryptographie post-quantique : étude du décodage des codes QC-MDPC

National audienceIn this work, I look at a variant of the McEliece cryptosystem aiming at reducing the key size. This scheme is based on correcting codes and itrelies on a simple probabilistic decoding algorithm. However the failures of the decoding algorithm can be used to retrieve the secrete key. During my internship I tried to reduce that decoding failure rate by introducing as little complexity to the algorithm as possible. Here, I present a few variants of the algorithm and look at how they perform on simulations. Finally I try to find models on the evolution of certain quantities during the algorithm. The knowledge of these evolutions could be used to improve the variants of the algorithm.Dans ce document, je m’intéresse à une variante du cryptosystème de McEliece visant à réduire la taille des clés. Ce système se base sur la théorie des codes correcteurs et utilise un algorithme de décodage itératif probabiliste simple. Cependant, les échecs au décodage peuvent être utilisés pour récupérer la clé secrète. Pendant mon stage, j’ai essayé de réduire ce taux d’échec au décodage en introduisant aussi peu de compléxité que possible dans l’algorithme. Ici, je présente quelques variantes de cet algorithme et je regarde leurs comportements sur des simulations. Enfin, j’essaie de trouve des modèles sur l’évolution de certaines quantités intervenant dans l’algorithme.La connaissance de ces évolutions pourrait être utilisée pour améliorer les variantes de l’algorithme