A New Relationship between the Nakagami “m-coefficient” and the S4 Index for more accurately Describing the Fading Distribution of Ionospheric Scintillation

The radio system designers have to be aware of the statistical characteristics of the instantaneous variation of signal amplitudes in order to develop possible mitigation strategies. The applicable scopes of the Nakagami distribution and the Rayleigh distribution are analyzed based on the observations of the amplitude scintillations recorded in the low-latitude of China. It’ concluded that the scintillation amplitude is more likely to obey the Rayleigh distribution when the S4 index is greater than 0.7. By the variation of “m-coefficient”, the Nakagami distribution could represent the Rayleigh distribution. Therefore, a new relationship between the S4 index and the “m-coefficient” of the Nakagami distribution is put forward, which can much better describe the fading distribution of amplitude scintillations in the whole range of S4 and also is simple enough for the engineering application.