A Low-Complexity Decision Feedforward Equalizer Architecture for High-Speed Receivers on Highly Dispersive Channels

This paper presents an improved decision feedforward equalizer (DFFE) for high speed receivers in the presence of highly dispersive channels. This decision-aided equalizer technique has been recently proposed for multigigabit communication receivers, where the use of parallel processing is mandatory. Well-known parallel architectures for the typical decision feedback equalizer (DFE) have a complexity that grows exponentially with the channel memory. Instead, the new DFFE avoids that exponential increase in complexity by using tentative decisions to cancel iteratively the intersymbol interference (ISI). Here, we demostrate that the DFFE not only allows to obtain a similar performance to the typical DFE but it also reduces the compelxity in channels with large memory. Additionally, we propose a theoretical approximation for the error probability in each iteration. In fact, when the number of iteration increases, the error probability in the DFFE tends to approach the DFE. These benefits make the DFFE an excellent choice for the next generation of high-speed receivers.Fil: Pola, Ariel Luis. Universidad Nacional de Cordoba. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Electronica. Laboratorio de Comunicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cousseau, Juan Edmundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación En Ingeniería Eléctrica; Argentina. Universidad Nacional del Sur; ArgentinaFil: Agazzi, Oscar E.. Irvine Center Drive. ClariPhy Communications; Estados UnidosFil: Hueda, Mario Rafael. Universidad Nacional de Cordoba. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Electronica. Laboratorio de Comunicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Companding and Predistortion Techniques for Improved Efficiency and Performance in SWIPT

In this work, we analyze how the use of companding techniques, together with digital predistortion (DPD), can be leveraged to improve system efficiency and performance in simultaneous wireless information and power transfer (SWIPT) systems based on power splitting. By taking advantage of the benefits of each of these well-known techniques to mitigate non-linear effects due to power amplifier (PA) and energy harvesting (EH) operation, we illustrate how DPD and companding can be effectively combined to improve the EH efficiency while keeping unalterable the information transfer performance. We establish design criteria that allow the PA to operate in a higher efficiency region so that the reduction in peak-to-average power ratio over the transmitted signal is translated into an increase in the average radiated power and EH efficiency. The performance of DPD and companding techniques is evaluated in a number of scenarios, showing that a combination of both techniques allows to significantly increase the power transfer efficiency in SWIPT systems.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

Adaptool: un entorno gráfico para procesamiento adaptivo

En el presente trabajo se presenta un entorno gráfico diseñado en base a un ambiente de cálculo numérico y matricial y una interface gráfica disponibles, que denominamos genéricamente Adaptool. La premisa fue generar un ambiente para la simulación y evaluación de problemas específicos de filtrado adaptivo de señales, con énfasis en aplicaciones de ecualización, identificación de sistemas y cancelamiento de interferencias con filtros adaptivos de realización IIR. La premisa de diseño del entorno es su modularidad, de forma que el mismo pueda ser expandido tanto en sus aplicaciones como sus prestaciones, de forma simple y consistente.Eje: AplicacionesRed de Universidades con Carreras en Informática (RedUNCI

DNA Barcoding Identifies Argentine Fishes from Marine and Brackish Waters

DNA barcoding has been advanced as a promising tool to aid species identification and discovery through the use of short, standardized gene targets. Despite extensive taxonomic studies, for a variety of reasons the identification of fishes can be problematic, even for experts. DNA barcoding is proving to be a useful tool in this context. However, its broad application is impeded by the need to construct a comprehensive reference sequence library for all fish species. Here, we make a regional contribution to this grand challenge by calibrating the species discrimination efficiency of barcoding among 125 Argentine fish species, representing nearly one third of the known fauna, and examine the utility of these data to address several key taxonomic uncertainties pertaining to species in this region..This study constitutes a significant contribution to the global barcode reference sequence library for fishes and demonstrates the utility of barcoding for regional species identification. As an independent assessment of alpha taxonomy, barcodes provide robust support for most morphologically based taxon concepts and also highlight key areas of taxonomic uncertainty worthy of reappraisal

Pilot-Based TI-ADC Mismatch Error Calibration for IR-UWB Receivers

International audienceIn this work, we first provide an overview of the state of the art in mismatch error estimation and correction for time-interleaved analog to digital converters (TI-ADCs). Then, we present a novel pilot-based on-line adaptive timing mismatch error estimation approach for TI-ADCs in the context of an impulse radio ultra wideband (IR-UWB) receiver with correlation-based detection. We introduce the developed method and derive the expressions for both additive white Gaussian noise (AWGN) and Rayleigh multipath fading (RMPF) channels. We also derive a lower bound on the required ADC resolution to attain a certain estimation precision. Simulations show the effectiveness of the technique when combined with an adequate compensator. We analyze the estimation error behavior as a function of signal to noise ratio (SNR) and investigate the ADC performance before and after compensation. While all mismatches combined cause the effective number of bits (ENOB) to drop to 3 bits and to 6 bits when considering only timing mismatch, estimation and correction of these errors with the proposed technique can restore a close to ideal behavior. We also show the performance loss at the receiver in terms of bit error rate (BER) and how compensation is able to significantly improve performance

Analysis of the CFO Successive Interference Cancellation for the OFDMA Uplink

The uplink of orthogonal frequency division multiple access or single-carrier frequency division multiple access suffers multiple access interference when carrier frequency offset (CFO) is not properly estimated and compensated. In particular, multicarrier uplink CFO compensation is highly complex due to the multiuser context. Successive interference cancellation algorithms are effectively employed to compensate for the CFO, where the interference produced by each user is handled sequentially through a series of iterations. The main contribution of this work is the analysis of the CFO compensation performance of efficient successive cancellation algorithms. We study the mean square symbol error, and derive a useful upper-bound of the compensation technique performance at convergence. This result extends the general convergence results for the space-alternating generalized expectation-maximization algorithm in the CFO compensation scenario. Finally, we validate the analysis with numerical simulations.Facultad de IngenieríaInstituto de Investigaciones en Electrónica, Control y Procesamiento de Señale