Experimental study of MIMO-OFDM transmissions at 94 GHz in indoor environments

Millimeter wave (mm-wave) frequencies have been proposed to achieve high capacity in 5G communications. Although meaningful research on the channel characteristics has been performed in the 28, 38and 60 GHz bands ─in both indoor and short-range scenarios─,only a small number of trials (experiments) have been carried out in other mm-wave bands. The objective of this work is to study the viability and evaluate the performance of the 94 GHz frequency band for MIMO-OFDM transmission in an indoor environment. Starting from a measurement campaign, the performance of MIMO algorithms is studied in terms of throughput for four different antenna configurations.This work was supported in part by the Ministerio de Economía y Competitividad MINECO, Spain under Grant TEC2016-78028-C3-2-P, and in part by the European FEDER funds

Performance of likelihood ratios considering bounds on the probability of observing misleading evidence

This is a pre-copyedited, author-produced version of an article accepted for publication in Law, Probability & Risk following peer review. The version of record Jose Juan Lucena-Molina, Daniel Ramos-Castro, Joaquin Gonzalez-Rodriguez; Performance of likelihood ratios considering bounds on the probability of observing misleading evidence. Law, Probability and Risk 2015; 14 (3): 175-192 is available online at: http://dx.doi.org/10.1093/lpr/mgu022In this article, we introduce a new tool, namely 'Limit Tippett Plots', to assess the performance of likelihood ratios in evidence evaluation including theoretical bounds on the probability of observing misleading evidence. To do that, we first review previous work about such bounds. Then we derive 'Limit Tippett Plots' that complements Tippett plots with information about the limits on the probability of observing misleading evidence, which are taken as a reference. Thus, a much richer way to measure performance of likelihood ratios is given. Finally, we present an experimental example in forensic automatic speaker recognition following the protocols of the Acoustics Laboratory of Guardia Civil, where it can be seen that 'Limit Tippett Plots' help to detect problems in the calculation of likelihood ratios

On the influence of diffuse scattering on multiple-plateau diffraction analysis at mm-wave frequencies

A study of the impact of the diffuse scattering phenomenon when calculating radio wave multiple-plateau diffraction losses at millimeter-wave (mm-wave) frequencies is hereby presented. In this sense, measurements of the total attenuation caused by a series of either rough or polished brick blocks are properly compared with the theoretical multiplediffraction losses of an array of ideally smooth brick blocks predicted by a hybrid uniform theory of diffraction-physical optics (UTD-PO) formulation. The results show the influence of diffuse scattering phenomena when it comes to calculating radio wave multiple-plateau diffraction attenuation and can be applied to the obtaining of more realistic mm-wave propagation models when multiple diffraction over rectangular obstacles with irregular (rough) surfaces has to be considered.This work was supported by the Ministerio de Economía y Competitividad (MINECO), Spain (TEC2016-78028-C3-2-P) and in part by the European Fonds Européen de Développement Économique et Régional Fund

Traffic noise mitigation using single and double barrier caps of different shapes for an extended frequency range

The primary function of noise barriers is to shield inhabitants of affected areas from excessive noise generated by road traffic. To enhance the performance of noise barriers while simultaneously adhering to height restrictions, the attachment of structures (caps) of different shapes to the tops of conventional screens can be considered. These caps can significantly impact the diffracted sound energy, thereby increasing the desired global acoustic losses. This work presents a comprehensive study of the acoustic performance of noise barriers with single and double attached caps of different shapes through a calculation of their insertion losses (IL). This study comprehensively addresses and compares different types, sizes, combinations, and numbers of noise barrier caps for different scenarios (including sloping and absorbent grounds) and sources (“car” and “ambulance”) for an extended frequency band up to 10 kHz. To the best of the authors’ knowledge, this is a range that has not previously been analyzed. A variety of different cap shapes were considered including cylinders, rectangles, trapezoids, and Y/T-shaped forms. To calculate the IL, an innovative and fast uniform theory of diffraction (UTD)-based method developed by the authors was applied in all simulations. The results showed that the Y-shaped single and double barrier caps were, in general, the most effective at increasing IL without raising the height of the barrier, thereby successfully managing the aesthetic impact. The results also showed how the consideration of sloping and absorbent floors could also contribute to improved noise abatement.This work was funded by the Ministerio de Ciencia e Innovación, Spain (TEC2016-78028-C3-2-P and PID2019-107885GB-C33), and by the European Fonds Européen de Développement Économique et Régional (FEDER) funds

UTD-PO formulation for the analysis of multiple-plateau diffraction when considering illumination from a low source

A hybrid uniform theory of diffraction-physical optics (UTD-PO) formulation for the analysis of the multiple-diffraction (MD) that takes place over rectangular-shaped obstacles (plateaus) when the latter are illuminated from a low source is presented. The solution, which is based on Babinet’s principle, has been validated with measurements taken at 60 GHz on a scaled model of the environment under study and with additional measurements performed by other authors. Moreover, the proposed approach has been compared with the wide-angle Fourier split-step parabolic equation method, with the UTD-PO formulation showing better accuracy against the experimental data, especially when the distance between the transmitter and the receiver is increased. Furthermore, the main advantage of the proposed solution is that due to recursion, the calculations imply only single diffractions, thereby avoiding the need of higher order diffraction terms in the diffraction coefficients. The results and findings of this communication are particularly applicable to the planning of microcellular mobile communication systems when the transmitting antenna is located below the height of the surrounding buildings.This work was supported in part by the Ministerio de Ciencia e Innovación, Spain under Grant TEC2016-78028-C3-2-P and Grant PID2019-107885GB-C33/AEI/10.13039/501100011033 and in part by the European Fonds Européen de Développement Économique et Régional (FEDER) Funds. Ignacio Rodríguez-Rodríguez would like to thank the support of Programa Operativo Fonds Européen de Développement Économique et Régional (FEDER) Andalucía 2014–2020 under Project UMA18-FEDERJA-023 and Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech., Spain

A simplified model for path loss estimation in Citrus Plantations at 3.5 GHz

Agriculture 4.0 represents a considerable increase in the number of sensors, as well as the appearance of new wireless technologies, which will meet the need to efficiently plan radio communication systems in agricultural environments. In this letter, a simplified model for path loss estimation in citrus plantations is proposed. The model assumes that, for long distances, the physical mechanism is a parallel transmission path over the treetops that can bemodeled by multiple-knife-edge diffraction. In our scenario, where the height of the transmitter is above the height of the trees, we proposed to estimate the multiple-knife-edge diffraction contribution by the settled field defined byWalfisch and Bertoni. In this way, the propagation losses estimated by the model have been compared with measurements carried out at 3.5 GHz in a lemon plantation before and after the fruit were collected. It has been observed that the slope of the regression line of the measurements yields values of 3.6 (with fruit) and 3.7 (without fruit), which are close to the value estimated by the model (3.8). The standard deviation of the prediction error given by the difference of the observed and estimated values is 4.5 dB (with fruit) and 3.2 dB (without fruit).This work was supported in part by the Fundación Séneca, Agencia de Ciencia y Tecnología de la Región de Murcia, Spain, through project 20804/PI/18, included in the Regional Program for the Promotion of the Research (2019) of the Fundación Séneca, Agencia and by the Ministerio de Ciencia e Innovación, Spain under Grant PID2019-107885GB-C33

Una función de atenuación expresada en términos de coeficientes UTD para la difracción múltiple de ondas esféricas en comunicaciones microcelulares

This work presents an explicit formulation for multiple edge diffraction for mobile radiowave propagation in terms of UTD-diffraction coefficients when a spherical incident wave is considered. The solution sharply reduces the computing time over existing formulation, specially when the number of edges is very large. The applicability of the result is interesting for both area coverage and interference predictions in microcellular systems.Los autores agradecen a la Dirección General de Ciencia, Tecnología y Sociedad de la Información (Consejería de Ciencia, Tecnología, Industria y Comercio de la Comunidad Autónoma de la Región de Murcia) la financiación de este trabajo (2I02SIU0019)

Medidas del canal MIMO en la transición de entrada a un pequeño tunel

This contribution investigates the MIMO channel by means of measurements at the entrance of a small tunnel at 2.4 GHz. The wireless channel is measured within 100MHz for a 4x4 MIMO system. It focuses on variations of the transmitter offset and on different antenna spacings, in order to understand the impact of different configurations on capacity. It will be shown that capacity is sensitive to the transmitter offset. Indeed, these measurements showed than it is possible to maintain a low distance between antenna elements if the transmitting offset is increased.Los autores agradecen al Ministerio de Educación y Ciencia (TEC2004-04866-C04-04/TCM) y a la Fundación Séneca (PPC/01444/03) por financiar este trabajo

Una solución híbrida UTD-PO para el análisis de la difracción múltiple de una serie de cilindros asumiendo incidencia de onda esférica

A new hybrid uniform theory of diffraction-physical optics (UTD-PO) formulation for the analysis of the multiple diffraction caused by an array of cylinders, assuming sphericalwave incidence, is hereby presented. The solution, validated with numerical data from technical literature, is mathematically less complex and computationally more efficient −for a large number of cylinders− than other existing methods, due to the fact that high-order diffraction terms (slope diffraction) are not considered, without such lack of terms barely entailing any loss in accuracy. Results can be applied in radiowave propagation analysis when multiple diffraction over rounded obstacles has to be considered.Los autores agradecen al Ministerio de Educación y Ciencia (TEC2007-66698-C04-04/TCM) y a la Fundación Séneca de Murcia (03133/PI/05) la financiación de este trabajo

Bosentan and oral anticoagulants in HIV patients: what we can learn of cases reported so far

Pulmonary arterial hypertension is an infrequent but nevertheless serious life-threatening severe complication of HIV infection. It can be treated with bosentan and oral anticoagulants. Bosentan could induce the acenocoumarol metabolism and it increases the INR values. Until now, no study of interaction between bosentan and oral anticoagulants in HIV patients has reported. So we present a case of this interaction between these drugs and we reviewed MEDLINE to identify all the papers published so far. In our case, several weeks after increasing dose of bosentan acenocoumarol dose had to be progressively increased to 70 mg/week (+33%) without obtaining an adequate INR level (2.0–3.0). Forty-nine days later, we achieved a therapeutic INR with 90 mg/week of warfarin. The use of bosentan and oral anticoagulants together in these patients require a closer monitoring during first weeks of treatment, after increasing the bosentan dose and even during longer periods of time