Effect of the local propagation model on LOS microcellular system design

Linear microcells have been proposed for PCS systems employing low base station antennas. The layout of linear cells in such a system will depend on the characteristics of the propagation on line-of-sight (LOS) radio links, which have been measured by various groups. For planning purposes, it is common to use a power law dependence of the path loss on distance, together with slow fading statistics, both of which are obtained from the measurements by the regression analysis. The simplest regression analysis fits a single straight line to measurements of path loss (dB) plotted versus the logarithm of the antenna separation. However, it has been found that a two-segment regression fit gives a more accurate representation for the trend of the path loss variation, and as a consequence results in a smaller standard deviation for the slow fading statistics. In this paper, we show how the use of the two-segment regression leads to a more efficient system design employing less base stations to achieve the same quality of service (QOS).