Instantaneous frequency estimation of frequency modulated signals in the presence of multiplicative and additive noise: Application to mobile communication systems

In this paper, we address the problem of estimating the instantaneous frequency (IF) of an FM modulated signal in the presence of multiplicative and additive noise processes. In particular, we consider the estimation of the IF of the received signal at the mobile unit antenna. We show that the existing non-parametric methods based on the Wigner-Ville spectrum (WVS) fail to extract the desired signal. Instead, the first moment of the Wigner-Ville distribution (WVD) of the signal can be used to estimate the IF of the signal under consideration. The estimator is unbiased and analytical expressions for the variance of the estimator in the absence and presence of additive noise are given.