A Unified Probability Density Function for Small Scale Fading Envelopes

We present a new probability density function (PDF) based on the generalized Laguerre expansion that, for the first time, completely characterize the widest range of small scale fading distributions in wireless communications. This unified PDF formula characterizes the most general case of small scale fading consisting of an arbitrary number of specular waves plus diffused power. The same formula covers all existing distributions for small scale fading, which include the Nakagami, Rician, and Rayleigh fadings, as special cases.