Unapređenje metoda merenja fedinga u RF telemetrijskim sistemima srednje naponskih distributivnih mreža

Abstract

In this paper, the estimation of Nakagami-m short term fading severity parameter and signal envelope average power are considered. Two methods enabling calculation severity parameter of Nakagami-m fading and are average power of signal envelope propagation in Nakagami-m fading channel by using measured values samples of Nakagami-m random process is considered in this work. By using measured values moments of Nakagami-m random process can be calculated. Nakagami-m fading parameters can be evaluated from moments. In this paper is considered the case when fading parameters are calculated from the second moment and the forth moment. Also, the case when Nakagami-m parameters are calculated by using the first, the second and the three moment is studied. In this paper diversity technique is applied for evaluation Nakagami-m fading parameters by using method of moments. Used diversity technique has MRC (maximal ratio combining) receiver with two and three inputs operating over independent and identical multipath fading channel. Moments of MRC receiver output signal enable Nakagami-m fading parameters evaluation. The accuracy of obtained results increases as the number of samples increases, the order of diversity increases and when the number of realizations increases. The second method studied in this paper, for estimating the Nakagami-m fading severity parameter and average power of Nakagami-m fading signal envelope is level crossing method. Level crossing rate is calculated for three values of signal envelope and from these three equations evaluated Nakagami-m parameters. Obtained expressions for level crossing rate are simple and Nakagami-m parameters can be determined. MRC diversity technique is applied for the estimation of Nakagami-m fading severity parameter and Nakagami-m signal envelope average power. The accurately of calculated values for Nakagami-m parameters increases as the number of samples increases, the number of realization increases and MRC diversity order increases. Also the accurately of obtained reports is higher for lower values of Nakagami-m fading severity parameter. *Application diversity technique for estimation of Nakagami-m fading parameters by using the method moments is not considered in open technical literature. *Level crossing rate method for estimation of Nakagami-m fading parameters is not considered in open technical literature.