Laboratory experiments for understanding effects of RF impairments on received signal in satellite link

Satellite communication becomes a complacent subject for undergraduate students as not many high end equipment or accurate, clear and well interpreted simulated results are available. Given this limitation in the availability of resources, conducting a laboratory becomes a challenging task. Hence, this paper has been carried out as an extension of Radiofrequency satellite Link on Matlab r2016b. The electromagnetic signal carrying information is inflicted upon a lot of impairments such as Free Space Path Loss, Memoryless Nonlinearity, etc. In the current Simulink radio frequency (RF) satellite Link model, these impairments are modeled in the form of respective blocks with the provision of various mask parameters in each of them which allows us to vary those parameters to see the corresponding changes in the nature of the signal. The primary objective of this paper is to carry out experiments on the similar lines as aforementioned dealing with all impairments and corresponding results are discussed followed by a conclusion. Increasing free space path loss led all the signal points coming closer to each other in their constellation diagram. Memoryless nonlinearity due to High Power Amplifier (HPA) tends to greatly displace all the points in a circular fashion from grid/square form. Thermal noise at the receiver has its effects on the outer constellation points. Phase noise spreads the signal points across their usual location. In-phase/Quadrature phase (I/Q) of the 16-QAM modulated signal's amplitude and phase change led to dynamic motion of signal points oscillating towards In-phase amplitude and Quadrature-phase amplitude axes.