Performance analysis of κ-μ distribution for Global Positioning System (GPS) L1 frequency-related ionospheric fading channels

Abstract

The present work aims to evaluate the application of the κ-μ distribution as a representation of the fading effect caused by the phenomenon of scintillation on L-band transionospheric radio links. The ionospheric scintillation is a phenomenon defined as a rapid variation in the amplitude and phase of electromagnetic wave signals. This phenomenon starts in the first hours of the night, at latitudes near the geomagnetic equator. Scintillation occurs when radio signals cross ionospheric irregularities, also known as plasma bubbles. These plasma bubble structures are generated after the sunset due to instabilities in the F region of ionosphere. Distributions with non-single parameter usually present better results, however, this point requires further investigation by comparing different models. The goals of this study are: (1) the modeling of experimental data using the κ-μ distribution; (2) the κ-μ parameters characterization for empirical data and the evaluation of parameters estimation based in different approaches; (3) the comparison between the distribution proposed and other models adopted in the literature in order to verify the performance of two parameter models. The results of the analysis performed showed that the κ-μ distribution presents good fitting of the empirical scintillation data. These fitting results were calculated through the chi-square fit test under which the values reveal fair E[χ2] for κ-μ distribution in most of the cases. The evaluation of κ-μ parameters suggests that the distribution has a more conservative outcome than in the distributions traditionally used, but being a legitimate approximation due to its adjustable features in the tail region of the distribution. Typical pairs of κ-μ coefficients are presented for theoretical works. The comparison of κ-μ distribution to Rice, Nakagami-m and α-μ models showed that κ-μ is capable of describing more severe scintillation scenarios where the tail of the distribution is more raised in comparison to the other models.

Keywords

• ionospheric scintillation
• fading distributions
• statistical modeling
• GNSS availability
• GNSS positioning issues