Statistical Modeling of the Performance of Steerable Directional Antennas in Femtocells

Abstract

This thesis investigates the effectiveness of using directive antennas in outdoor-to-indoor fixed wireless links based on empirical data. In our initial study, we present thegain advantage of a steered directive antenna over an omnidirectional one. We findthat as much as 14 out of 16 dB of free-space antenna-gain are attainable even in richindoor scattering conditions. At the same time, no larger fade margin is required. Wesubsequently extend our study considering as a reference for comparison a spatialarray of omnidirectional antennas instead of a single element. We thus compareangular to spatial diversity. We find that for such systems, angular diversity verysignificantly outperforms spatial diversity. To provide a reference for the observedresults we consider a simple propagation model, which is analyzed theoretically andvia simulation. This model is found to match our empirical results very well and canthus be used to predict the performance of diversity systems for the type of settingswe considered.