The UWB-OFDM Channel Analysis in Frequency

2009

In this paper, the ultra-wideband channel with orthogonal frequency division multiplexing (UWB-OFDM) is analyzed in the frequency domain. For UWB-OFDM channels with log-normal fading in the time domain, we show that the amplitude of each subcarrier can be approximated by a Nakagami-m random variable, where the fading parameter, the mean power and the correlation coefficient are expressed in terms of the following parameters: time arrival of the clusters, inter-arrival time of rays inside clusters, and power decay constants of rays and clusters.

Cocaine-induced coronary thrombosis and acute myocardial infarction

2004

A 26-year-old man was admitted to our hemodynamic laboratory because of an anterior AMI and post myocardial infarction angina. He is an active smoker (10 cigarettes/day) and consumes inhaled cocaine during weekends (the last consumption of cocaine was 1 week ago). No others risk factors were recorded. Initial electrocardiogram shows sinus rhythm and anterior QS complex (V1–V3) with anterolateral ST segment elevation (V1–V5, D1 and aVL). Creatine-kinase isoenzyme MB and Troponin I were elevated at arrival. Upon admission, the patient was normotensive but with signs of pulmonary congestion. Ventriculography showed anterolateral and apical hypokinesia with an ejection fraction of 21%. Coronari…

¿Es segura y eficaz la correcta anticoagulación con antagonistas de la vitamina K en fibrilación auricular?

2020

Temporal Dispersion Characterization of Over-Building Propagation Applied to Iso-Frequency Repeaters

2009

This letter presents the results of a measurements campaign carried out at 2050 MHz with the aim of characterizing the time dispersion of multipath propagation when the transmit and receive antennas are placed near and situated on rooftops or mounted on masts. The measurements were taken in four separate locations within the urban area of Madrid, Spain. From the measured data, the root mean square (RMS) value of the delay spread and the delay interval that characterize the time dispersion propagation of the environment under study are analyzed. An average power delay profile (PDP), representative of the time dispersion, is proposed so as to extrapolate these results to other similar environ…

Application of alternating projection method to ensure feasibility of shadowing cross-correlation models

2007

A novel procedure based on the alternating projection method to adjust experimental shadowing cross-correlation (SCC) matrices is proposed. Given an SCC matrix derived from any experimental model, this procedure finds the nearest diagonalisable correlation matrix. This adjustment allows a proper simulation of shadowing samples, since it produces correlation matrices for which Cholesky factorisation is feasible. Simulation results using this procedure for three different SCC models are compared and discussed.

Time dispersion characterization for UWB mobile radio channels between 3.1 and 10.6 GHz

2007

In this paper, a characterization of the UWB mobile radio channel time dispersion is presented. The results provided were obtained from a measurement campaign carried out in a typical indoor office scenario in the band from 3.1 to 10.6 GHz. Time dispersion metrics as delay spread, coherence bandwidth, delay interval and delay window, in both line-of-sight (LOS) and non-line-of-sight (NLOS) conditions are provided.