Robustness of Digitally Modulated Signal Features Against Variation in HF Noise Model
High Frequency (HF) band has both military and civilian uses. It can be used either as a primary or backup communication link. Automatic Modulation Classification (AMC) is of an utmost importance in this band for the purpose of communications monitoring; e.g., signal intelligence and spectrum management. A widely used method for AMC is based on Pattern Recognition (PR). Such a method has two main steps: feature extraction and classification. The first step is generally performed in the presence of channel noise. Recent studies show that HF noise could be modeled by Gaussian or bi-kappa distributions, depending on day-time.