JPL's Wireless Communication Reference Website

Chapter: Wireless Channels
Section: Path Loss

Micro-Cellular Path Loss

Microcellular networks use a cell size of, say, 200 to 2,000 meters. Propagation models for micro-cellular communication typically model the path loss law as a transition from free-space propagation to groun wave propagation if d < dg where theoretically the turnover distance dg occurs at dg < 4hR hT / l, where d is the distance of the radio link under study, hR and hT are the heights of the receiving and transmitting antenna respectively, and l is the wavelength of the transmitted wave.

Various models have been proposed, e.g. a step-wise transition from "20 log d" to "40 log d" at a certain (turnover) distance.

A smooth transition is often considered in theoretical system studies.

Multipath in Micro-Cells

The micro-cellular propagation channel typically is Rician fading: it contains a dominant direct component, with an amplitude determined by path loss, a set of early reflected waves adding (possibly destructively) with the dominant wave, and intersymbol interference caused by the excessively delayed waves, adding incoherently with the dominant wave.

JPL's Wireless Communication Reference Website 1993, 1995.