Fading Evaluation in the mm-Wave Band

[EN] A thorough millimeter-wave measurement campaign is carried out in an indoor environment with an aim at characterizing the short-term fading channel behavior. The measurements are conducted in a variety of scenarios, with frequencies ranging from 55 GHz to 65 GHz, in line-of-sight and non-line-of-sight conditions, and combinations of horizontal and vertical polarizations at both transmitter and receiver. A number of fading models are tested, namely Rayleigh, Rice, Nakagami-m, alpha-mu, kappa-mu, eta-mu, and alpha-eta-kappa-mu. The statistics under analysis are those characterizing the fading amplitude and the frequency selectivity. In particular, the probability density and cumulative distribution functions for the former and level crossing rate per bandwidth unit for the latter are the respective first-and second-order statistics used. To this end, from the experimental data, the parameters of the models are estimated and the corresponding theoretical curves are plotted and compared with the empirical ones. Whereas the required theoretical formulations of the first-order statistics of these models are already well known, those of the second-order statistics as well as these fitting process in such a band shown here are unprecedented in the literature.This work was supported in part by CNPq under Grant 304248/2014-2 and Grant 308365/2017-8 and in part by RNP, with resources from MCTIC, Grant No. No 01250.075413/2018-04, under the Radiocommunication Reference Center (Centro de Referencia em Radiocomunicacoes -CRR) project of the National Institute of Telecommunications (Instituto Nacional de Telecomunicacoes -Inatel), Brazil, and by the Ministerio de Economia, Industria y Competitividad of the Spanish Government under the national project TEC2017-86779-C2-2-R, through the Agencia Estatal de Investigacion (AEI) and the Fondo Europeo de Desarrollo Regional (FEDER). The associate editor coordinating the review of this article and approving it for publication was T. Kim.Rufino Marins, TR.; Dos Anjos, AA.; Rodrigo Peñarrocha, VM.; Rubio Arjona, L.; Reig, J.; Amaral De Souza, RA.; Yacoub, MD. (2019). Fading Evaluation in the mm-Wave Band. IEEE Transactions on Communications. 67(12):8725-8738. https://doi.org/10.1109/TCOMM.2019.2941493S87258738671

On The Efficient Generation Of Alpha-kappa-mu And Alpha-eta-mu White Samples With Applications

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This paper is concerned with a simple and highly efficient random sequence generator for uncorrelated alpha-kappa-mu and alpha-eta-mu variates. The algorithm may yield an efficiency of almost 100%, and this high efficiency can be reached for all special cases such as alpha-mu, kappa-mu, eta-mu, Nakagami-m, Nakagami-q, Weibull, Hoyt, Rayleigh, Rice, Exponential, and the One-Sided Gaussian. This generator is implemented via the rejection technique and allows for arbitrary fading parameters. The goodness-of-fit is measured using the Kolmogorov-Smirnov and Anderson-Darling tests. The maximum likelihood parameter estimation for the kappa-mu distribution is proposed and verified against true values of the parameters chosen in the generator. We also provide two important applications for the random sequence generator, the first one dealing with the performance assessment of a digital communication system over the alpha-kappa-mu and alpha-eta-mu fading channels and the second one dealing with the performance assessment of the spectrum sensing with energy detection over special cases of these channels. Theoretical and simulation results are compared, validating again the accuracy of the generators.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [501281/2013-4

Efficient acceptance-rejection method for nakagami-m complex samples

The aim of this Letter is to propose simple and efficient simulation means for the Nakagami-m complex signal using the acceptance-rejection algorithm. Two methods are envisaged: (i) one for the general case, which includes both fading and phase parameters; and (ii) another for the particular case, which includes only the fading parameter. In both cases, the samples are drawn from easily-implementable hat functions found in closed-form. For the general case, the efficiency is always in excess of 70% reaching 100% depending on the parameters. For the particular case, the efficiency moves rapidly towards 100% for useful values of the parameter31949

Multiantenna Spectrum Sensing in the Presence of Multiple Primary Users over Fading and Nonfading Channels

The basis of this paper is Wei and Tirkkonen, 2012, in which expressions for the key performance metrics of the sphericity test applied to the multiantenna cooperative spectrum sensing of multiple primary transmitters in cognitive radio networks over nonfading channels are provided. The false alarm and the detection probabilities were derived in Wei and Tirkkonen, 2012, based on approximations obtained by matching the moments of the test statistics to the Beta distribution. In this paper we show that the model adopted in Wei and Tirkkonen, 2012, does not apply directly to fading channels, yet being considerably inaccurate for some system parameters and channel conditions. Nevertheless, we show that the original expressions from Wei and Tirkkonen, 2012, can be simply and accurately applied to a modified model that considers fixed or time-varying channels with any fading statistic. We also analyze the performance of the sphericity test and other competing detectors with a varying number of primary transmitters, considering different situations in terms of the channel gains and channel dynamics. Based on our results, we correct several interpretations from Wei and Tirkkonen, 2012, in what concerns the performance of the detectors, both over a fixed-gain additive white Gaussian noise channel and over a time-varying Rayleigh fading channel