A Measurement-Based Model for Predicting Coverage Areas of Urban Microcells

We have performed data reductions on 900 MHz signal attenuations measured on numerous streets in Manhattan. The data base consists of both local spatial averages of signal attenuation and the short-term fluctuations about this average. The former, which we call the local mean attenuation (LMA), is our primary focus. We use the data base to obtain contours of constant LMA for two neighborhoods and find the contours to have the shapes of convex diamonds. We propose that squares inscribed within these contours be used as the “building blocks” of microcellular environments. A theory is developed that explains the contours and predicts, with reasonable accuracy, the sizes of the inscribed squares. We show, moreover, that the prediction method can be applied without the need for measured data. Finally, we examine the short-term fluctuation statistics of the signal attenuation, showing them to be Rayleigh-like in the non-line-of-sight regions of a microcell and Rice-like in the line-of-sight region. We discuss possible extensions of this work to other frequency bands and other urban environments.