Analysis of nonlinear signals in the presence of Rayleigh fading

One of the applications with nonlinear nonstationary signals lies in mobile communications where nonlinear information bearing signals are faded by the time-varying propagation medium. Consequently, the envelope of the received signal is often modelled by a Rayleigh distribution. This Rayleigh fading severely degrades the performance of the mobile radio transmission system. Diversity reception or a method based on higher-order statistics have been proposed to cope with this effect. This paper presents an alternative method for estimating the instantaneous frequency (IF) of linear FM and BFSK signals affected by Rayleigh stationary random process appearing in the application of mobile communications. The method is based on the use of a second order Cohen´s class of time-frequency distributions