The performance evaluation of communication protocols in broadband fixed wireless access (BFWA) networks needs the accurate description of the statistical properties of the packet error process. In BFWA networks mainly operating above 20 GHz, a clear line-of-sight (LOS) path is necessary between the base stations (BS) and the subscribers (S). Rain attenuation is the dominant fading mechanism at these frequencies. In this paper, a Markov- based method to estimate the packet loss rate (PLR) performance over a dynamically, due to propagation, varying LOS BFWA channel is presented and tested against simulation results. The proposed method is based on the first- order Markovian modeling of the rain attenuation process. The proposed method can serve as a performance evaluation tool of various modulation and coding schemes (MCS) and is also applicable even when adaptive fade mitigation techniques are employed in the BFWA network.