Multiple-antenna-aided OFDM employing genetic-algorithm-assisted minimum bit error rate multiuser detection

The family of minimum bit error rate (MBER) multiuser detectors (MUD) is capable of outperforming the classic minimum mean-squared error (MMSE) MUD in terms of the achievable bit-error rate (BER) owing to directly minimizing the BER cost function. In this paper,wewill invoke genetic algorithms (GAs) for finding the optimum weight vectors of the MBER MUD in the context of multiple-antenna-aided multiuser orthogonal frequency division multiplexing (OFDM) .We will also show that the MBER MUD is capable of supporting more users than the number of receiver antennas available, while outperforming the MMSE MUD

Shedding light on lipase stability in natural deep eutectic solvents

This study presents the potential role of natural deep eutectic solvents (NADESs) in a lipase-catalyzed hydrolysis reaction as both a co-solvent in an aqueous solution and as a main solvent. Ammonium salts such as choline chloride (ChCl) were paired with different hydrogen bond donors such as glycerol and malonic acid and sugars (glucose, fructose and sucrose). The hydrolysis of p-nitrophenyl palmitate by six different lipases: lipase from porcine pancreas (PR), lipase from Candida rugosa (CR), Amano lipase PS, from Burkholderia cepacia (AM), lipase from Rhizopus niveus (RN), lipase acrylic resin from Candida antartica (ARC), lipase B Candida antartica immobilized on Immobead 150, recombinant from Aspergillus oryzae (CALB), were tested in five NADESs. The results showed that NADES3 prepared from ChCl/sucrose was the most promising solvent as it enhanced the activities of both CALB and lipase from porcine pancreas to 355 % and 345 %. The kinetics investigation confirmed the higher catalytic efficiency (kcat/Km) of lipases in the 40 % of (NADES3) and compared with the aqueous form. The trend achieved by NADES may be a promising approach for applications and further perspectives as genuinely green industrial solvents

Ternary glycerol-based deep eutectic solvents: physicochemical properties and enzymatic activity

The present study investigates deep eutectic solvents (DESs) as potential media for enzymatic hydrolysis. A series of ternary ammonium and phosphonium-based DESs were prepared at different molar ratios by mixing with aqueous glycerol (85%). The physicochemical properties including surface tension, conductivity, density, and viscosity were measured at a temperature range of 298.15 K – 363.15 K. The eutectic points were highly influenced by the variation of temperature. The eutectic point of the choline chloride: glycerol: water (ratio of 1: 2.55: 2.28) and methyl triphenylphosphonium bromide:glycerol: water (ratio of 1: 4.25:3.75) is 213.4 K and 255.8 K, respectively. The stability of the lipase enzyme isolated from the porcine pancreas (PPL) and Rhizopus niveus (RNL) toward hydrolysis in ternary DESs medium was investigated. The PPL showed higher activity compared to the RNL in DESs. Molecular docking simulation of the selected DES with the substrate (p-nitrophenyl palmitate) towardPPL was also reported. It is worth noting that ternary DES systems would be viable lipaseactivators in hydrolysis reactions

Genetic Algorithm Assisted Minimum Bit Error Rate Multiuser Detection in Multiple Antenna Aided OFDM

The family of minimum bit error rate (MBER) multiuser detectors (MUD) is capable of outperforming the classic minimum mean-squared-error (MMSE)MUDin term of the achievable bit-error rate (BER) owing to directly minimising the BER cost function. In this paper, we will invoke genetic algorithms (GA) for finding the optimum weight vectors of the MBERMUDin the context of multipleantenna aided multi-user OFDM

Minimum Bit Error Rate Multiuser Detection in Multiple Antenna Aided OFDM

In this contribution, we propose a Minimum Bit Error Rate (MBER) multiuser detector for Space Division Multiple Access (SDMA) aided Orthogonal Frequency Division Multiplexing (OFDM) systems. It is shown that the MBER detector outperforms the Minimum Mean Squared Error (MMSE) detector, since the MBER detector directly minimizes the BER, while MMSE detector minimize the mean-squared error (MSE), which does not guarantee achieving the minimum BER. When supporting two users, the proposed MBER scheme substantially outperforms the classic MMSE arrangement in the investigated propagation scenario

LDPC and Turbo Coding Assisted Space-Time Block Coded OFDM for H.26L

In this contribution we propose an LDPC assisted Space-Time Block Coded OFDM transceiver designed for wireless video telephony and characterise its performance when communicating over the UTRA wideband vehicular fading channels. Low Density Parity Check (LDPC) and turbo channel coding schemes are invoked. By concatenating a space-time block coded OFDM scheme with powerful channel codes, the performance of the system can be substantially enhanced. The LDPC codec outperformed the turbo codec in terms of both the achievable video and transmission frame error rate performance

LDPC and Turbo Coding Assisted Space-Time Block Coded OFDM

Space-time block coded OFDM is capable of achieving substantial diversity gains, while supporting high bit-rates in wireless communications. By concatenating a space-time block coded OFDM scheme with powerful channel codes, the performance of the system can be further enhanced. In this contribution both Low-Density Parity-Check (LDPC) coding and turbo coding assisted $G_2$ space-time block coded OFDM is investigated. The achievable performance is studied as a function of the number of iterations, coding delay, code rate and decoding complexity