The $\eta$ - $\mu$ Joint Phase-Envelope Distribution

This letter derives a simple and closed-form expression for the phase-envelope joint distribution of the eta-mu fading environment, a general fading model that includes the Hoyt and the Nakagami-m models as special cases. In the same way, the marginal distribution of the phase is also obtained in an exact closed-form expression. The phase distribution is then used in order to derive the probability density function (pdf) of the envelope time derivative, which, as opposed to the Nakagami-m and Rice models, is not Gaussian