Experimental results on the level crossing rate and average fade duration for urban fixed wireless channels

The temporal behavior of fixed wireless (FW) links is usually described in terms of fade depth distribution, level crossing rates and average fade duration. This knowledge is needed for the optimization of transceiver parameters such as modulation format, frame length, automatic gain control dynamics, etc. We present analytic and empirical results on the level crossing rate (LCR) and average fade duration (AFD) in FW links. We show that under certain conditions the LCR and AFD do not depend on the shape of the Doppler spectrum and that with a proper choice of parameters, expressions that have been justified for mobile wireless links are also applicable to FW. Results of extensive measurements validate the assumptions that sustain our model